Reciprocity Timer 1.0

[Boinzo]

Hi All. I have just had Apple accept my first iPhone App into the store! It is a simple little app I originally made for my own use that I thought others might also get some value from.

It allows you to select from a list of available films and a metered exposure duration - from there it will calculate an actual exposure including reciprocity. The maths is based on as many formaulas I could find for some common films. You can currently select from Ilford B+W, Velvia (color filtered and unfiltered), Provia, Tri-X and Ektar. I will be more than happy to add new films if anyone has the mathematics and can send it to me.

The app also includes a slider to let you add or remove stops of initial exposure (for example if you add an ND) and gives you a count-down timer to time-out your shutter.

It's pretty simple - but I have found it really useful.These (http://www.largeformatphotography.info/forum/showthread.php?t=79804) shots were made using it.

I have it listed at $1.99 - but will obviously review that depending on feedback and workload.

You can get it here (http://itunes.apple.com/au/app/reciprocity-timer/id459691262?mt=8).

[SMBooth]

Been hoping for something like this, will download and give it a try.

[jeroldharter]

It would be useful to know all of the films included.

[Boinzo]

The included films are listed in my post. I am also happy to add new films as the maths comes to hand!

[jeroldharter]

OK. I did not notice that. What I should have said is that I wish it had TMY2!

[Boinzo]

Have you got a chart of times? I can try to calculate a best fit formula for it and add it if you have. If you have some useful data for other films just pm me!

[sultanofcognac]

Just downloaded it – looks very interesting and will put it to the test this weekend ;-)

How about Acros 100 and Efke films?

Good luck in the future and thanks for what looks like a good tool!

[David Aimone]

tmax 100 and 400; Efke 25 and 100; Acros 100 are those I use the most. Looks good.

[Steve Goldstein]

Nice-looking and useful app, well done.

Is there any value in some sort of zoom function on the filter slider to trade less range for finer resolution, like 1/2 or 1/3 stop? I don't use filters that need 9 stops of compensation, but usually use 1-1/3 stop for my polarizer. So maybe the full +-9 stop range in 1-stop steps as now, and a second with +-3 stop range in 1/3 stops???

[Light Guru]

Any chance of adding Velvia 100?

[Steve Goldstein]

Hi Stef,

The times you list in the "Metered Exposure" column differ slightly from those that you'd read off a light meter dial, for example 15sec instead of 16sec. How did you choose the times?

[SW Rick]

I think the "bell" at the end is WAY too loud- the iphone volume doesn't lower it. I'm embarrassed to use it in public. Please either drop it or make it user-controllable.

[jeroldharter]

Does anyone have a table of verified reciprocity times for various films (e.g. TMY2)?

I have not yet downloaded the app because it does not include my primary film. I wonder if it could include user programmable tables that feed the controls/dials on the app?

[Boinzo]

Thanks for all the suggested improvements guys. I will certainly take those suggestions on board and make some changes. You can expect an update soon.
The times I selected for metered exposure were really just arbitrary so I will look at making them more closely match a spot meter.
I'll turn down the bell. Sorry! I'm a bit deaf....:)
I will also look at changing the slider to provide some finer control. I have a lee big-stopper. Hence the 10 stops...
I did want to make it possible to add your table but this is complex and might be a while away.
I will also try to add some more film types while I am doing an update. If anyone has reliable references for formulas I am keen to see them. One issue I have found is that there are many conflicting tables and formulas...
Thanks for the feedback guys and thanks for trying it out. I'll see what I can do to address the suggestions!

[jeroldharter]

I went ahead and downloaded the app. I think it has good potential.

Apart from adding additional films, some additional features might include:

A toggle switch to calibrate the slider in 1/10, 1/3, 1/2, 1 stop increments

A link to tables with filter factors and stops including the math for combining filters

A link to bellows compensation information, and perhaps a second slider for bellows extension adjustments that could be enabled/disabled.

If it had Tmax films plus the above features I would be willing to pay more also.

[Allen in Montreal]

I bought the app too.

What would be a great addition is the development compensation that matches the chosen exposure.
ie: A 12 second metered exposure requires X time and -8% dev. etc.
That would be perfect.


I like Jeroldharter's idea about a bellows extension table.

I think in North America, it has to have T-Max tables to fly, T-max really seems to the number once choice of film here.

I agree the bell is a little loud if you are in a public place. I imagine shooting the interior of a cathedral. :eek:
For now, you can hold the phone so the speaker rests on the tip of your baby finger and it cuts the noise by 80 percent.

[Boinzo]

Hi all. I have submitted an update to the app to Apple for approval. Hopefully it will hit your phones in the next week or so.

I have added a bunch of films - including Kodak TMY, TMX, Velvia 100, and Efke. Among others. The maths for the black and white films is now largely based on the Gainer method as discussed here (http://www.apug.org/forums/forum37/11566-reciprocity-misbehavior-12.html) (thanks to SMBooth for putting me onto that article).

The Efke calculations are based on adding 1/3 rd of a stop to 10 secs, 1/2 stop to 100 secs and 2/3 of a stop after that.

I also messed with the Ilford math (splitting it out into separate films and using the Gainer method). The returned data for HP5+ is now a very close match to Ilfords published charts.

Please be aware that I don't personally shoot all of these films so I have no way to verify the calculations will result in correct exposure or negative density. If the numbers you get don't meet your real-world experience please send me your data tables and I'll try to make the required adjustments.

I have also added the ability to adjust the slider by 1/3, 1/2 or 1 Stop increments.

I also tamed the loud bell and made sure it adjusts with the volume control as expected.

I like the bellow extension suggestion - but I only shoot wide angle and have never needed to calculate it. If someone can give me a definitive reference I'll look into it.

Thanks again for giving the app a try. And for all the great suggestions. Some of the more complex ones might take a little longer to implement but I have certainly taken them on board.

[jeroldharter]

Those are excellent and quick updates.

For extension factor:

Bellows length squared/focal length squared=exposure factor

Example:

Extension = 300 mm
Focal length = 210 mm
Extension factor = 90000/44100=2.04

So the extension factor is ~2, or 1 stop.

A metered exposure of 1/4 sec would then be 1/2 second.

[Boinzo]

Thx! I have implemented 2 sliders. One for extension and one for focal length. This seems to work well but I am wondering what the highest values should be? I have implemented it with 10mm to 500mm range. Does that seem right?
I can have this feature included in the current release which should then cover off on all the main requests so far.

[jeroldharter]

For large format, 90 - 600 mm should cover. I think Olympus made a 35mm macro for 35mm film.

So 35-600 should cover film based scenarios.

[SW Rick]

Thanks for your prompt action on our suggestions, esp. the bell :) - makes for a better product and happy user base! Will note this in itunes.

[Boinzo]

Hi Again! So I have implemented bellows extension with 2 sliders between 30mm and 600mm as you can see in the screen grab below.

Now - my concern is that the sliders are a bit difficult to adjust accurately over such a large range. Eventually I might push focal length out into a setup page where you enter your and select your lens. But right now I want to get this updated for you guys that have already downloaded it.

My question is - what accuracy do you guys use when measuring this stuff? The sliders would be easier to use if I made them move in 5mm increments (for example). But will this make the accuracy of the exposure calculation unacceptable? I am thinking about making the sliders go 30,35,40,45 etc... in my tests it seems to take a change of around 5mm to change exposure by 1 second on a 10 second exposure.

I am a bit concerned that anyone with big fingers might struggle to set the sliders right where they want them.

Any thoughts?

[jeroldharter]

That looks much better. For me, the 5mm increments would be fine.

Is the first slider in the picture a filter factor adjustment?

If possible, it would be nice to have a link to a table of common filter factors.

[jeroldharter]

By the way, is the updated version available? I can't find it. Thanks.

[Boinzo]

Ok - I'll roll it up at 5mm increments. It just makes it easier to use.

The first slider is filter factor -yes. I agree a table would be nice. Some of those features will be part of a bigger app I have in mind that will incorporate this functionality. It'll take a bit longer to do though!

The updated version wont be available until Apple approves it. That usually takes 5-7 days. Once it's approved it'll just appear as an update within App Store on your phone and you'll be able to install it from there.

[Will Whitaker]

Glad to see the support. I've just purchased it.

[SMBooth]

Can you explain how this works, do you now need to set the bellows at the the len focal length each time you use it? So 90 for a 90mm lens when there is no bellow ext to worry about?

Sorry my bad another look at the image and I see that the len / bellow is separate and just gives a stop value to add

[Boinzo]

Ok guys. After spending all day on this... here's where I am at.

I have added a table of filter values - some may need a bit of editing. I based the data on this (http://en.wikipedia.org/wiki/Filter_factor#Filter_factors_for_common_filters) page at Wikipedia.

Someone let me know if they are no good - I rarely use any of these so aren't sure. Some of the values look a bit high to me.

Effectively you will now be able to hit the little circular blue arrow button to access a list of filters. These can be added (as many as you like) to the exposure calculation. You can clear them all out as well.

The slider is now just an additional compensation device for times when your filter isn't in the list - like my Lee Big Stopper!

So basically there are 4 things that impact the exposure time. Film and Metered Time selection, the adjustment slider (in Whole, Half or Third Stops), the Filters you add and the Bellows Compensation you set.

I need to do some more testing before I release this to Apple for approval but thought you might like to see the progress so far. It's now a pretty complex app so I need to re-make-sure I don't have any memory leaks etc.

Hopefully Apple will have it tomorrow so you guys should get an update about a week or so later.

Future additions will include ability to add and manage your own filters and lenses but I might need to do some work for some actual clients tomorrow! :rolleyes:

Here's some pix...

[Steve Goldstein]

This is a really useful app, thanks for undertaking it.

The new additions look great. I'm not sure you really need to carry around the UV and Skylight filters.


What would be really cool, and a lot more work, would be a light meter (spot, of course) with this functionality. As good as this app is, metering is still a 2-step process - read the exposure, then compensate for reciprocity. It's always been thus. But imagine one of those Sekonic meters, that already contains a micro, that gives direct exposure time when you're in fixed-aperture mode. That would be sweet!

Hmmm, I have a friend with contacts at Sekonic...

[rdenney]

This is perfect. Don't clutter it up with a personal lens library or anything like that--no need to have to maintain a database that then can't be transferred to a new phone.

For those focused in the far field who don't need a bellows extension factor, one can just leave the sliders all the way to the left with no need to worry about the focal length.

And if someone doesn't want to use the timer, they don't have to. I like software that provides features that stay out of the way when not needed.

And as for me, I don't need this capability in a meter. I want the meter to be simple and predictable, with the fewest number of buttons to push. I think that desire is pretty common, and the reason the classic Pentax spot meters are still so popular.

Rick "who bought it already and is looking forward to the upgrade" Denney

[Steve Goldstein]

As I've given a little more thought to a reciprocity-compensated meter, I've realize that to be really useful the meter would need to be much more sensitive than any on the market today. I don't see that happening, but will pursue with Sekonic nevertheless.

I'm also a big fan of simple meters, and have both analog and digital Pentax models. But if I have to make a reading with gadget A, then transfer the info and push some buttons on gadget B, I don't see that life would be worse if gadget A had the optional capability to do the work of gadget B.

I don't want to get into an argument, I'm just saying...

[rdenney]

As I've given a little more thought to a reciprocity-compensated meter, I've realize that to be really useful the meter would need to be much more sensitive than any on the market today. I don't see that happening, but will pursue with Sekonic nevertheless.

I'm also a big fan of simple meters, and have both analog and digital Pentax models. But if I have to make a reading with gadget A, then transfer the info and push some buttons on gadget B, I don't see that life would be worse if gadget A had the optional capability to do the work of gadget B.

I don't want to get into an argument, I'm just saying...

No argument--just an aspect you might not have considered. It seems to me that reciprocity failure varies quite a lot over different films, and including it in a meter would require some way to enter the film type as well. Keeping that sort of data on the meter seems to me a hassle.

If you have pull with Sekonic, get them to reissue the L-488 with a low price tag.:)

(By the way, in looking at the meter in my Canon 5D, it does seem to have built in the reciprocity failure of the sensor in its calculation. I discovered this comparing it to a traditional meter. But it should tell you that your idea makes a lot of sense--if you know what film you are using.)

Rick "who'd rather have two simple and fool-proof gadgets than one that can be easily programmed wrong" Denney

[ljsegil]

Just happy to have bought your app and support all your good work.
LJS
?Porta 160 and 400?

[Allen in Montreal]

Great work, thank you.
I have been toying with mine for ideas to improve but you have beat me to them!:)
Looking forward to the bellows draw addition and the T films.





Ok - I'll roll it up at 5mm increments. It just makes it easier to use.

The first slider is filter factor -yes. I agree a table would be nice. Some of those features will be part of a bigger app I have in mind that will incorporate this functionality. It'll take a bit longer to do though!

The updated version wont be available until Apple approves it. That usually takes 5-7 days. Once it's approved it'll just appear as an update within App Store on your phone and you'll be able to install it from there.

[Boinzo]

Hi Again! I just wanted to let everyone know that it's taken me a little longer to get the update submitted to Apple than I had hoped. The app got a lot more complicated this week and it took me some time to finish and to completely test it. It is now submitted to Apple so I hope you will be getting the update soon.

The new version now includes an editable table of common photographic filters. This is accessed by touching the little notepad icon. You can select a filter and edit its details to suit your needs. So if you know that your CPL requires 1.4 stops of compensation you can enter that in and the app will remember that value. You can then apply your CPL to the reciprocity calculation. You can move back and forth between the main screen and the table adding as many filters as you want (or to clear them all out of the calculation).

As I said it also now includes bellows extension, lots more films and the ability to add manual compensation in whole, 1/2 or 1/3 stops increments.

Thanks again for all the suggestions and the supportive comments.

BTW: With respect to Portra films - I couldn't find much on reciprocity for these. But what I did find seemed to indicate that you could probably use the calculation for Efke B+W film and come out pretty close.

Here's some screen grabs of the new app....

[leetmode]

thanks a lot for this boinzo, please let us know when apple accepts it!

[Steve Goldstein]

I just downloaded rev 1.1 from Apple. It looks great. Thank you.

Are the arrow, plus, and times buttons supposed to have different functions on the filter page? They all seem to revert back to the main timer.

[Boinzo]

Hi Steve.
Yeah - I just saw Apple had approved it. Hooray.

The Back Arrow button just takes you back to the main page. It does nothing else.

The Plus button adds the currently selected filter's exposure factor into your maths and then goes back. You will see the filter and its factor appear on the main page. If you go back and forth between the filter list and the main screen pressing the plus you can add more than one filter to the exposure.

The X Button removes all filters from your exposure calculation so you can start over.

When you have a filter selected you can hit the pencil icon to make edits to it. So you can rename the filters and modify their exposure factors to more closely match what you use.

Enjoy.

[Lachlan 717]

Boinzo,

Thanks for the App.

One (hopefully not too stupid) question: What is the difference in the Velvia 50 tabs (filtered/unfiltered)?

Thanks.

[Boinzo]

Hi Lachlan. You're welcome!
There are no stupid questions!

I had 2 sets of maths and figures. One (filtered) is if you have a colour-correction filter attached to deal with Velvia's known colour shift on long exposures. The other is if you don't.
Hope that makes sense!

[Steve Goldstein]

Thanks for the filters explanation. I only noticed that all buttons took me back, but missed the time changes. Feeling a bit dumb about that, the numbers are certainly big enough!

[jeroldharter]

I am using it on an iPad. Is it hard to "upsize" the app for iPad?

[Boinzo]

Hi Jerold. Unfortunately it's basically a separate app. It would take a lot of effort to make it fill the iPad screen.
My original design was to have something I could use out hiking in the mountains or next to the sea. Something I could fit in my pocket. I never take my iPad on those trips!

[jeroldharter]

Just wondered. It works fine on my iPad.

On the larger screen I was envisioning sliders for f stop, shutter speed, then the adjustments, a field for notes, a field for exposure number, and a save feature. Ability to attach an iPad photo would be ideal. Kind of like the BTZS software disengaged from film development data, but appealing to a broader audience. I would pay a lot more for that.

[SW Rick]

Just wondered. It works fine on my iPad.

On the larger screen I was envisioning sliders for f stop, shutter speed, then the adjustments, a field for notes, a field for exposure number, and a save feature. Ability to attach an iPad photo would be ideal. Kind of like the BTZS software disengaged from film development data, but appealing to a broader audience. I would pay a lot more for that.

While I understand the desire for an all-in-one, things tend to get complicated and wind up with bloated dslr-like menus and sub-menus. Have you looked at Lenny Eiger's PhotoToolsPro app, which does most, if not all, of what you're describing?

There's virtue in doing a few things well, which is why the Pentax spotmeters have an advantage over the Sekonic in terms of ease of use and not needing to carry the manual with you.

Rick

[jeroldharter]

Good point.

However I assume it could be designed with smart toggle to disable unwanted features and make for a simpler interface.

For someone with no Mac skills, I have a lot of ideas.

[SW Rick]

Good point.

For someone with no Mac skills, I have a lot of ideas.


Hey, you're an Artist, not a coder :)

[Boinzo]

I do have another app I am working on that will do much more than this one but it's still some time away. It will come at things from a different perspective and provide many more features to support the film workflow.

But I agree I will need to be careful not to make a "sekonic" where a Pentax would do.

In any case I hope the new version meets most people's needs for the task of getting more accurate and repeatable long exposures. And thanks again for all the suggestions and comments. Tell your friends to buy it!

I firmly believe it's possible to be both an artist and a coder! :)

[Erik Larsen]

I'm not sure if it's possible, but it would be nice if the reset button would reset the filter factor so you do not have to go to the filter screen to do it. Just a thought. I think I will be using your app a lot, Thanks!
regards
Erik

[Boinzo]

Hi Erik. I know what you mean and I just couldn't decide between the two options. On one hand if you are going to make another exposure you may well leave the same filters in place and just bracket or something. On the other hand you might change lenses and/filters and shoot another frame.

I figured which ever way I did it it was going to not work for someone... Sorry.

If the consensus of comments is that reset should zero the filters I'll make the change in the next update.

Thanks for the input. And glad the app is working for you.

[jeroldharter]

I have been playing around with the TMAX 400 and filter sliders. As far as I can tell, the filter factors shown on the sliders become the f stop corrections on the main page. For example, when I add a red filter with a filter factor of 8, the exposure is then adjusted by 8 stops instead of 3 stops.

[Boinzo]

Oh no! :eek:

Sorry - I just checked and I had omitted the log maths for the filter factors. I think I was too fixated on making the filters editable! :mad:

I have fixed this and re-submitted to Apple. Once again the update will take a few days.

When it arrives the filter maths will be correct based on multiplication factors. In the mean time if you edit the filters to show actual stops of compensation required you will get the correct exposure. So if you change the Red filter's factor from 8.0 to 3.0 you'll get correct times.

Sorry for the error.... :o

[jeroldharter]

That's ok. Thanks for being so quick with the changes.

[SMBooth]

While your fixing thing you cannot make changes to the lower filter factors as the keyboard get in the way and you cannot scroll the display up far enough.

[Boinzo]

Ok. I have made some changes to allow for editing of the bottom rows of the filter table. Thanks for pointing that out.
I also made it so that the sliders all disable when you start the timer. This is just to prevent accidentally moving them during an exposure and throwing the time out.
This is all submitted to Apple so you should have an update in due course.

[SMBooth]

I bet you wish you never started this now don't you :)

[Boinzo]

Hahaha. No. It's all good. :-)
I am hoping everyone is happy now though! ;-)

[Allen in Montreal]

There is a new update posted today

[Boinzo]

That's right! Apple have approved the latest update. Hopefully this release will address everyone's requests. :-)

I'd appreciate it if those that have bought the app and found it useful could take a few seconds to review and/or rate it on the app store. Supporting this little app will help me to move forward on developing some more photography tools I have in mind!

Thanks again everyone for all your suggestions and support.

[jeroldharter]

I have another suggestion. I understand that the purpose of the app is to figure out the exposure time corrected for reciprocity taking into account the variables. But sometimes, you don't know in advance that reciprocity will be an issue.

For example, if you use TMY2 (TMAX400), with a 1/8 second base exposure, a filter and some bellows compensation the resulting exposure might be 1/2 second. But the program won't show you that.

So the suggested change is to add a field above the Reset button that shows the actual shutter speed that the program calculates formatted in usual photographic notation, e.g. 1/4, 1/2, 1", 1.5", 2"...

[Boinzo]

Thanks for the input.
I have looked at implementing this but it is a little complex because the app can easily generate shutter speeds with small fractions of a stop. To achieve sensible "standard" shutter speed notations is a bit difficult - I end up with shutter speeds like 1/33, 1/62, 1/12 for example...
In any case - I am looking into it but the primary purpose of the app is to calculate and time reasonable shutter speeds for longer exposures where reciprocity is an issue.

[Dcohio]

Just purchased the app this week and got to use it this morning. Very usefull! Times listed where very close to my highly refined total guesstimations that I typically use. Thanks for giving me something I can actually use on my phone other than playing games.
Thanks,
Doug

[Boinzo]

I'd just like to say thanks for the positive comment! I appreciate it. I'm really pleased you are finding my little app useful.
I'd really love it if people who are using the app would take a moment to submit a review on the app store...
Thanks again to all that have purchased the app!

[jb7]

Hello-

I downloaded this ages ago, haven't used it yet-

One thing, I've searched through the thread, but haven't seen this as an issue-
the app timer doesn't seem to work in the background- which might be useful for my current setup- Efke 25, dark interior, 72XL, centre filter, f/16. Computed time is around 15 mins...

When the phone goes to sleep, which I think is reasonable, for battery conservation, the timer just pauses, until it is woken up again. Any chance of making it run in the background, or am I missing something?

Other than that, good app, well done-

[Erik Larsen]

Hello-

I downloaded this ages ago, haven't used it yet-

One thing, I've searched through the thread, but haven't seen this as an issue-
the app timer doesn't seem to work in the background- which might be useful for my current setup- Efke 25, dark interior, 72XL, centre filter, f/16. Computed time is around 15 mins...

When the phone goes to sleep, which I think is reasonable, for battery conservation, the timer just pauses, until it is woken up again. Any chance of making it run in the background, or am I missing something?

Other than that, good app, well done-
I've experienced that hiccup as well. It would be nice if the timer didn't go to sleep:) other wise a very nice app.
Regards
Erik

[Boinzo]

Guys. I am looking into the timer issue. It did not used to do this ... Playing a sound should be enough to keep the app from deep sleeping...but it certainly seems to be an issue now. I will try to implement a fix for this ASAP. Thanks for bringing it to my attention.

[Boinzo]

It used to be fine on IOS4 because it was playing a sound.... (this is supposed to stop the device from going in to sleep mode).

Ok. So making the timer stay alive was not an option (this violates Apple's Development Guidlelines - something to do with battery life). :(

So. Instead I have managed to make it time how long it is asleep for and compensate accordingly when it wakes up. Also - if it goes to sleep with more than 30 seconds left it will create a system alert at 20 seconds to go to remind you to wake it up. If your exposure has less then 10 seconds to go when it goes to sleep - it'll throw an alert at the end of the exposure time to tell you to shut your ... umm.. shutter.

Thanks for bringing this to my attention. Most of my use has been at times of under 30 seconds so it had not come up for me.

I am pleased you are getting good use out of the app. The new version with this fix will automatically appear once Apple have approved it. This usually takes about 7 days.

I'd appreciate it if those using the app would take the time to jump on iTunes and rate it for me. Every bit helps.... :)

[SW Rick]

Thanks for your continuing interest in keeping your product current and useful!

[jb7]

Very good, thank you, appreciate your continued support of the app-

[Boinzo]

Apple have approved the update. So your App Store icon should have a little red number on it!
Thanks all. I hope this fix makes the app more useful for you.

[Steve Goldstein]

Just downloaded version 1.5. Thanks for your continuing efforts on this slick and useful app.

[Ken Lee]

I just got the app - brilliant!

Here are 2 suggestions from a software engineer/photographer :rolleyes:

1) The focal length and bellows extension sliders are great for moving a large distance, but once you get close to your desired number, they are hard to adjust with fine control, on an iPhone at least. In cold weather, I imagine it would be even harder. If there were > and < arrows (or +/- buttons) then we could finely increment/decrement the numbers simply by clicking. So don't remove the sliders, just augment them with a finer control that is easy to adjust with fat fingers.

2) Perhaps I'm alone in this, but I generally think about my lens first, and bellows draw second. ("I'm using a 210mm lens. Done. Now what is the bellows extension ? 250mm. Done") not ("I've got 273mm of bellows extension. Now what lens am I shooting with again ?"). So I'd like to have the lens selection appear before the bellows extension. That's less important of course, and I may be in the minority.

[jb7]

Thanks for doing that-

There's still a bit of an issue with the timer- if I switch to the app when I receive the alert, the timer counts down from the last two seconds- effectively cutting the time by nearly twenty seconds. Not a big deal, but if I have to manually count out the last few seconds, then a 5 second alert might be more accurate than 20. Or rather, more convenient- If the alert contained the end of the countdown timer, that would be perfect.

However, in the grand scheme of things, and considering the application of the app, at those sort of times, perhaps a 20 second difference might be unmeasurable on film anyway.

It just results in me standing around for a bit longer, lips moving, mumbling, not really a great look...

[Boinzo]

Thanks for doing that-

There's still a bit of an issue with the timer- if I switch to the app when I receive the alert, the timer counts down from the last two seconds- effectively cutting the time by nearly twenty seconds.

How long does it takes you to unlock the phone? The timer keeps running as this is happening. The 20 second notification is not second accurate because the phone will queue this alert. It's meant to simply give you time to get back into the app. Perhaps it should just say "exposure is ending soon" to more accurately reflect that.

There is another issue Ken found where just starting and sleeping the app is enough to get you an exposure alert sometime later. I am looking into this.

It serves me right for trying to get the update out too quickly!

[jb7]

It only takes a couple of seconds to get back into the app. I've checked the overall time against a stopwatch, and the difference is around 20 seconds-

[Boinzo]

Ok. So I have done another update.

The timer is definitely accurate to within a second or two on long exposures! Even after phone call interruptions and sleeping. I have done many tests over and over at various durations.

I fixed Ken's issue with the notifications. And I have added fine adjustment buttons for focal length and bellows extension. I have also swapped the position of the two sliders as per Ken's suggestion. This makes sense and I don't know why I didn't do it in the first place!

While I was in there - I added the Big Stopper to the list of available ND Grads.

As always it's now with Apple. Should hit your phones by the end of the week.

Apologies for messing up the previous update. Was in a bit too much of a hurry I think.

And again thanks for the support!

[jb7]

Yes, sorry for the panic, the alerts were late, but the times were accurate- however, the lateness of the alerts seemed to also slow the stopwatch app, which I was using to time the timer, not being near any other timing device at the time-

Altogether a bit confusing, but I'm glad it works, and that I can be confident it works-


Sorry for the wobble...

[Ken Lee]

And again thanks for the support!

You should get an award for world-class customer support. :)

[Boinzo]

Yes, sorry for the panic, the alerts were late, but the times were accurate- however, the lateness of the alerts seemed to also slow the stopwatch app, which I was using to time the timer, not being near any other timing device at the time-

Altogether a bit confusing, but I'm glad it works, and that I can be confident it works-


Sorry for the wobble...

All good jb7. You only cost me $4 million in sales. My lawyers will be in touch... ;)


You should get an award for world-class customer support. :)

Haha. Thanks Ken. It's how I run my real software business. If I didn't I wouldn't be able to afford LF!

[SW Rick]

Haha. Thanks Ken. It's how I run my real software business. If I didn't I wouldn't be able to afford LF![/QUOTE]


Too bad you don't run most of the software companies I have to deal with.... :)

[J. Fada]

Wow, you have my two bucks. I look forward to trying it out! Almost all of the exposures I do with LF have reciprocity issues. I usually just eeny meeny it, but this app (hopefully) will let me be more accurate. Thanks.

[MWitmann]

Bought yesterday; will try it tomorrow.

Any chanche to have listed also the Portra 160?

Many thx

[Boinzo]

Bought yesterday; will try it tomorrow.

Any chanche to have listed also the Portra 160?

Many thx

I have always said I am happy to add new films if people can provide me with an appropriate formula or at least a list of times they find reliable.
It takes many hours of research to find the best data for each film and I can't make the time at the moment.
My initial research on Portra did not turn up much of value though which is why it isn't listed.
Hope you enjoy yet app and it works well for you. There is another update due this week.

[MWitmann]

I have always said I am happy to add new films if people can provide me with an appropriate formula or at least a list of times they find reliable.
It takes many hours of research to find the best data for each film and I can't make the time at the moment.
My initial research on Portra did not turn up much of value though which is why it isn't listed.
Hope you enjoy yet app and it works well for you. There is another update due this week.

many thanks

[SMBooth]

Regarding filter, I find when adding a yellow(8) filter (1 stop) makes no difference to the time, however if I add a red (25) filter (2 stop) it only adds one stop of time , eg 1/500 > 1/250

[Boinzo]

Regarding filter, I find when adding a yellow(8) filter (1 stop) makes no difference to the time, however if I add a red (25) filter (2 stop) it only adds one stop of time , eg 1/500 > 1/250

Check what you have as the filter factors. The value listed next to each filter is filter-factor not stops. So a 1 Stop Filter has a factor of 2.0x . A 10 Stop filter has a factor of 1024.0x. The skylight filter is 1.0x and so does not change exposure.

The default value for a Yellow filter is 2x when the app is installed. This is 1 stop. It changes a 1/500 exposure to 1/250 as expected in all my tests.

Of course you are free to edit these factors to more closely represent what you have in your kit. They are not over-written by an update.

[SMBooth]

OK that's the problem, my yellow was set to x1.0 which I assume to be 1 stop not as you say filter factor. I go through and fix. Thanks

For reference: http://myphotohome.com/pto/filters4.html

[Boinzo]

Apple have approved the latest update. This should improve the notifications and a couple of other little things (as suggested by Ken). It also adds the Lee Big Stopper 10 Stop ND to the filter list.
Enjoy!

[Ken Lee]

I installed the update. Now it's even better !

[r.e.]

The new + & - controls for 5mm changes in focal length and bellows extension are a good idea.

[Dcohio]

Like the updates. Makes it easier to adjust lense and bellows slider. Thank you

[Ken Lee]

I used it again this weekend. What a treat. It has paid for itself many times over ;)

[John Wiemer]

Thanks for all the work on this very useful app. Since you are using Filter Factors to determine the exposure changes, it seems to me that the FF for the polarizers should be between 3 and 4, not 1.6 (2/3 of a stop) as you have listed them. My experience in reading exposures through the filter is that polarizers generally have between 1 1/2 to 2 stop differences.

[Boinzo]

Hi John. Glad you are finding the app useful. The filter factors are editable to meet your requirements. Just select a filter and touch the pencil icon and enter the required factor as a decimal such as 3.0.
There is such a variation in different filters that people carry so I felt it best to allow you to enter your own and simply provide a starting point.
All the best Stef.

[John Wiemer]

Good point. I have done just that with my most used filters. I guess my point was that there are those who will use your filter factors as they are listed on the app as being totally correct. Rather than use a filter factor of 1.6 for the polarizer why not list it as 3 or 4 which is more accurate. A FF of 1.6 is about a one stop difference from 3 or 4. Wilkepedia has a good chart under "Filter Factors." Again, thank you for an excellent app. I have used it several times and find it very useful.

[Boinzo]

No problem. I'll change the default in the next release. That wiki page was one of my sources so perhaps I copied it wrongly!
Thanks again.

[Ken Lee]

Here's a set of Large Format photos (http://www.kenleegallery.com/html/tech/NineInchKershaw.php) made at close range with long exposures - all timed using the app.

[Michael W]

I have this app and it looks to be useful. I have noticed one thing that doesn't appear to be correct. If I set the exposure reading to 10 seconds and bring up Kodak Tri-X the app says the exposure should be 12 seconds. However according to the Kodak pdf for Tri-X the adjusted exposure should be 50 seconds.

[taulen]

Seems to be right about tri-x, at least that should be a quick fix =) If apple approves it ;)

[Boinzo]

Hey Guys. I'm away on a family holiday at the moment. I'll look into this when I get back to the office in 2 weeks.

[Allen in Montreal]

I was wonder about the bellows draw feature.
I really appreciate it and use it, but it falls a little short allowing only plus one stop. I ran out of calculations and had to dig up my homemade chart once it went beyond 1 stop.

Thanks for a great app!
Allen

[Ken Lee]

The bellows compensation is not limited to 1 f/stop.

Try a focal length of 30mm and a bellows extension of 600mm: the app tells you to apply a compensation of 8 2/3 stops.

What may be limiting, is the upper bound of 600mm. You're starting out with a long lens (410mm), and you have reached the upper bound.

An 8x10 camera with a 300mm normal lens, needs 600mm of extension just to reach 1:1 magnification.

An upper limit of 2000mm or greater might be overkill for most users, but it would put an end to requests to increase the number.

[Boinzo]

Thanks Ken. It's funny how it works. When I implemented the bellows extension feature I actually posted here for suggestions on an upper limit! 600mm seemed to be the suggestion (I have no experience with this because I shoot wide angle only). :)
I can push up the limit easily but it is a trade off between using the slider and the limit.
Would 1200mm work for most?

[Allen in Montreal]

Hi Ken,

I was actually shooting people, with a 16.5 red dot, which I really like. It is razor sharp and a length I like for portraits. I know many prefer the 14", which allows 1 2/3 for 23.6 inches of draw.

The rail on my 8x10 camera is 30 inches (762mm) but if anyone adds a second standard to that (which I do once in a while), it can hit 1143mm.
I really can't see myself ever going beyond that, but if the app went to outer limits, I could stop carrying my reference book. ;)

[Ken Lee]

I think beyond 1200, anyone can just drop the unit of measure altogether (mm/cm/inch, etc.)

After all, a 12mm lens at 24mm extension gets the same bellows compensation as a 1200mm lens extended to 2400mm - or a 12 inch lens extended to 24 inches.

It's the relationship between the two which matters, not the absolute unit of measure.

[corgan4321]

As soon as TMAX films are added, I'll buy it!

[Allen in Montreal]

As soon as TMAX films are added, I'll buy it!

T400
T100
TMZ

Are supported.

[Steve Hamley]

I just bought it - let's see how it works. Thanks Boinzo!

Cheers, Steve

[Russell Regnery]

Boinzo,

I noticed the app store description does not mention the Efke films as currently supported by your well reviewed application. And I also note that you offer to include additional films when data is provided. I found a link for reciprocity failure and Efke films that can be readily translated if necessary from the German:

http://www.fotoimpex.de/Technik/efkefilms/efke100/efke100.html

As large format Kodak films have become either essentially unavailable (e.g., Tmax 5x7) the Efke sheet film data should become more relevant to many of us. I hope this is useful...inclusion of Efke info in your app would be much appreciated.

Thanks much, Russ

[Boinzo]

Hi Russell.
Thanks. The app does support efke film already. Although I think it is not adding the 6th of a stop at 1 sec to 2 secs. In any case efke 25 is a film I use a lot and have certainly made many long exposures timed with the app on efke!
I am not at my desk ATM (away for the weekend). But I'll check exactly what math I am doing on efke and post it for you. If it needs some change I'll look into it.
Thanks again for the post!

[Allen in Montreal]

You could probably make a killing on a basic darkroom timer,

Just a basic timer, autorun is a must, 10 stages would be best, programmable and be able to name the steps and save.

Simple but no one has made the ideal simple timer yet.




http://www.largeformatphotography.info/forum/showthread.php?t=86345


http://www.largeformatphotography.info/forum/showthread.php?t=86345&page=4

[Roger Thoms]

I just started using the reciprocity timer and I works well, at least it did for the three exposures I used it on. It would be nice if the beeps were a little louder, I could barely hear them and yes the volume was up all the way. Also didn't see Tri-X 320 on there.

Roger

[thrice]

Any plans for an android version?

[Underaglassbell]

Hi All. I have just had Apple accept my first iPhone App into the store! It is a simple little app I originally made for my own use that I thought others might also get some value from.

It allows you to select from a list of available films and a metered exposure duration - from there it will calculate an actual exposure including reciprocity. The maths is based on as many formaulas I could find for some common films. You can currently select from Ilford B+W, Velvia (color filtered and unfiltered), Provia, Tri-X and Ektar. I will be more than happy to add new films if anyone has the mathematics and can send it to me.

The app also includes a slider to let you add or remove stops of initial exposure (for example if you add an ND) and gives you a count-down timer to time-out your shutter.

It's pretty simple - but I have found it really useful.These (http://www.largeformatphotography.info/forum/showthread.php?t=79804) shots were made using it.

I have it listed at $1.99 - but will obviously review that depending on feedback and workload.

You can get it here (http://itunes.apple.com/au/app/reciprocity-timer/id459691262?mt=8).

Hi, I purchased this app recently and used it for the first time today, in conjunction with the 'ND timer' app.

I was shooting with a roll of efke IR820 Aura (100) film, and I used your 'efke' setting; I take it that is right - meaning the Reciprocity is the same for most efke films, or have I got this wrong?


It seems a great app though. I would really love it if you could include Portra 160/400 in the next update, as I do tend to shoot with them quite frequently, and it would be nice to have them in the app for reference.


Regards,
DaN

[Geraldine Powell]

I don't understand how to use the reciprocity timer. I tried it for the first time yesterday and got a weird result that had to be wrong. Here is what I input:

HP5+ film.
the meter reading was f32 at 20sec, so I put in 20"
Focal length 120mm
bellows extension 300mm (That gave bellows: 2 and 2/3 srops)
no filters, so that was 0

That gave just over 25 MINUTES as the exposure time. What am I doing wrong?

Also, how do I prevent the iphone5 turning itself off during the countdown?

I read through all 12 pages of this thread but no-one seems to have had this problem.
Geraldine

[Ken Lee]

I entered the same parameters and got the same result, which may be perfectly correct.

An increase of 2 2/3 stops for bellows extension equates to a factor of 6.5x, so 20 seconds becomes 130 seconds.

If we look at the reciprocity table given by Ilford for HP5+, see see that 130 seconds is "off the chart", but perhaps the author of the software has determined the formula according to an exponential function.

By 30 seconds, the curve is basically linear, but rather steep: to go from 30 to 35 seconds of measured time (X axis) requires an additional 50 seconds of exposure (Y axis). At that rate (10 seconds compensation for each additional second), compensation might add up pretty quickly.

Am I overlooking something ? Perhaps some brighter lighting would help get things down to a more reasonable exposure.

http://www.kenleegallery.com/images/forum/HP5Reciprocity.png

[Geraldine Powell]

Thank you for the reply. I opened up 2 and 2/3 stops. Was that correct? Anyway, what I did to the lens aperture would not affect the app on the iphone. 25 minutes just seems too long compared to an other image I took under the same lighting. I am off now to process the negatives and I will report what I find.
Geraldine

[Ken Lee]

Opening up by 2 2/3 stops allows you to shorten the exposure by a factor of 6.5 X, so the 20 second indicated exposure goes down to 3 seconds.

Next, we consider reciprocity failure: the app tells us that a 3-second exposure with HP5+, should actually be given 6 seconds. That matches the Ilford chart too.

So if you compensated for bellows extension but not for reciprocity, you will have under-exposed by 1 stop.

Depending on the subject, that may or may not matter. If the subject is very contrasty, then some detail in the shadows will have been lost. If the subject is of low contrast and not particularly dark, then you can still get an optimal print.

[Geraldine Powell]

I don't understand why I need to shorten the exposure time if I have already opened up 2 and 2/3 stops. I thought you either open up the stops or you lengthen the exposure time, not both.
Anyway, I had the shutter open for 25 minutes at the settings I described. I expected total over exposure but actually the image looks good in the negative. I wil scan it tomorrow and then I will really be sure. Maybe the app was right on. The first negative I shot where I forgot reciprocity failure was grossly underexposed.
I think it would be very helpful if we or someone could make a tutorial of how to use this app so it is really clear to inexperienced people like myself.

[Ken Lee]

I don't understand why I need to shorten the exposure time if I have already opened up 2 and 2/3 stops. I thought you either open up the stops or you lengthen the exposure time, not both.
Anyway, I had the shutter open for 25 minutes at the settings I described. I expected total over exposure but actually the image looks good in the negative. I wil scan it tomorrow and then I will really be sure. Maybe the app was right on. The first negative I shot where I forgot reciprocity failure was grossly underexposed.
I think it would be very helpful if we or someone could make a tutorial of how to use this app so it is really clear to inexperienced people like myself.

You don't need to shorten exposure time. You needed to lengthen it because of bellows draw, and then some more for reciprocity. If you shot at infinity, there would be no need for bellows compensation. However, you shot at greater magnification than 1:1, so 2 2/3 stops more exposure were needed as compensation.

Next comes reciprocity failure. Some films handle long exposures better than others. This is a separate consideration from bellows extension, and needs to be calculated after bellows compensation - which is what the app does.

This page (http://www.kenleegallery.com/html/tech/bellows.php) gives the formula for bellows compensation (see the section entitled "How Many More f/stops are Required ?"). That the app is a lot more convenient.

Reciprocity varies with brands of film, and with length of exposure. Fuji Acros requires very little compensation, even for rather long exposures. More traditional films like Tri-X or HP5+ lie at the other end of the spectrum, and require a lot of compensation. So that app is actually pretty straightforward: you enter the parameters, and it tells you the results, quite reliably, and for a great range of variables.

I recently shot some close-up images near a window in an otherwise dark room. The metered exposures were several seconds, but with bellows draw and reciprocity, the required exposures were 40 seconds. I followed the app's recommendations and things worked out satisfactorily. Here's one of those photos.


http://www.kenleegallery.com/images/forum/s29.jpg
Antique Rulers, 2012
Sinar P, 210mm Macro Sironar
4x5 TMY, Diafine

[Boinzo]

Hi Geraldine

As the guy that wrote the app let me give you some insight....

Firstly a big thanks to Ken for his comments.

Ken is completely correct in his very detailed explanations as well as in his "guess" that the app is using an exponential formula to calculate out reciprocity beyond known values. The app supports as many films as I could find reasonable data for from fairly reliable sources and recreates the values as closely as possible. Other films have required the development of "formulas" that most closely approximate the published curves. These equations are always exponential in nature.

So some films in the app have more exact formulae based on the published experiences of many photographers and others less so. There is a little bit of voodoo about reciprocity calculation - different photographers have different approaches and beliefs. The app is really designed to give you a repeatable and reliable reference point. It should at no time over-ride your own experience, creativity or intuition. It does aim to give you some easy-to-use mathematics to get you as close as possible to a repeatable exposure in the current metered light. I do not warrant that it will create a perfect exposure on every film in every circumstance. And obviously I can't personally test every film. :-)

With respect to your exact situation - all I can say is that app will take your input exposure time - add any required filter factors as entered - then add any bellows extension as entered and then apply the appropriate reciprocity calculation to the resulting time.

I don't actually think a tutorial in using the app is necessary (in over 2 years this is the first request for something like that!) - the process itself is pretty simple so long as the photographer is clear about what elements of exposure are required in the situation at hand. It is important to understand how bellows extension (well explained above by Ken) and so on actually work. The app assumes the photographer is on top of all that stuff.

With respect to the earlier point about waking the device in long exposures - the app will raise a notification at 20 seconds remaining exposure warning you that your exposure will end soon giving you the ability to manually wake your device. The exposure countdown continues in the background when the phone is asleep and when you wake the device it will take up where it had left off.

It is actually against Apple's development guidelines and rules to create an app that keeps the device awake (doing so can result in flat batteries very quickly and prevent other apps like the phone from functioning correctly) - although some developers have used "hacks" like playing silent sounds to keep the device awake I chose not to. In part because I often use this app myself on very long hikes and do not want a flat battery!

I hope you continue to use the app and I am pleased the image you made relying on it was correctly exposed!

[Michael W]

Hi Boinzo - something I think I mentioned here a while back - the app is very good but the Tri-X times suggested by the app are wrong - they are the same as Tmax 400, whereas Tri-X requires more compensation, I know this from experience and the Kodak datasheet. Any plans to update this?

[Payral]

+1 for TXP 320 !

[Boinzo]

Hi Michael. How much more compensation does TriX require? Are you able to give some sense of the math? I'll take another look and see if can find anything!

[Michael W]

Hi Michael. How much more compensation does TriX require? Are you able to give some sense of the math? I'll take another look and see if can find anything!
I use the Kodak data sheet (https://docs.google.com/viewer?a=v&q=cache:uwmjYhPSVYUJ:www.kodak.com/global/en/professional/support/techPubs/f4017/f4017.pdf+&hl=en&gl=au&pid=bl&srcid=ADGEESgKdbsSLC_h0sx027Pwihmk6v020-f639MJAAf1Bx3_gb4aqmJYipzLj2mCBwIHin3LEEYjCTyncguQIrKwzelA8rh4H68orVfKNWF9Z3yV9PwyFHz9LWkLKEcbdNQaDiVHkFyy&sig=AHIEtbQKWLreCtH9ph2z2nWx9qgkUXBnMQ) which says if the meter suggests 1 second expose for 2 seconds; if the meter reads 10 seconds expose for 50 seconds and if the meter reads 100 seconds expose for 1200 seconds. That's all they give and I have found the times to be accurate. I'm not sure what the maths is or if you can work it out from that.

[Boinzo]

Thanks Michael. I'll look at what I can do... :-)

[tenderobject]

do you have kodak plus x and arista edu ultra 100/200/400 in your list of films?

[Noah A]

I use this app and love it. The timer itself is handy.

Any plans to add Portra 160? PLEASE????

[jose angel]

First of all, thank you Boinzo for your work and your attention.

Just two issues I have noticed; in the "filter section", when trying to overwrite the filter name (using the iPhone "typewriter"), the typewriter area gets off... it turns suddenly white. I then leave the "filter section", but when I return to it, the "typewriter area" is kept off and white. I`ve had to uninstall and re-install the app to make it work again.

The second one is not a bug, but a suggestion; the app screen is already too compressed with all the controls, it could take advantage of the bigger screen in the iPhone 5. Specially for the focal lenght&bellows extension sliders which are too small. In my iPhone 5, there is a wasted blank area at top and bottom. I wonder if the film selection controls can be placed in another screen, maybe leaving at the main screen a reminder or a small two or three buttons selector, for the most used films (at the end, these days we use to work with one or two kinds of film, so there is no need of having this big selector in a first plane).

I find it to be an useful app for LF photographers; yours have been a very good idea. I`m working with it today.

[tenderobject]

What films are available on this app? Will tryn o get this sooner

[Eric Bryan]

Purchased and downloading right now. Great utility!

[Boinzo]

Purchased and downloading right now. Great utility!
Awesome Eric. Hope it works well for you!


What films are available on this app? Will tryn o get this sooner

The app currently supports the following films. There are one or two obvious omissions - Astia, Provia and Portra for example - this is because all my research indicates that reciprocity is of minimal concern with these or I have simply been unable to find useful data.
The Tri-X times the app determines have been found to have some issues in the current release. These have been resolved and times that more accurately reflect Kodak's official data will appear in the next version. Along with a few other enhancements. I just need the time to complete it!


Velvia 50 (unfiltered)
Velvia 50 (with magenta filter)
Velvia 100F
Provia 100F
Ektar
Efke 25/50
Fomapan 100
Fomapan 200
Ilford HP5+
Ilford Delta 100
Ilford Pan-F+
Ilford FP4+
Ilford SFX 200
Ilford XP2
Kodak T-MAX 400
Kodak T-MAX 100
Kodak TRI-X
Kodak PLUS-X
Kodak Tech Pan
Kodak T400 CN
Kodak TMZ

[michael slade]

Tried to use it yesterday. I was disappointed that the apertures stopped below what I wanted to use. I was wanting to use f/128 but when I realized I couldn't, I just opened up the calculator and figured out my exposure on my own.

[Boinzo]

Tried to use it yesterday. I was disappointed that the apertures stopped below what I wanted to use. I was wanting to use f/128 but when I realized I couldn't, I just opened up the calculator and figured out my exposure on my own.

Hi Michael. I'm not sure I understand your issue. The app does not have any apertures in it. Can you give me a clearer idea of what you were trying to achieve in case it's an issue I need to address in the program?
Thanks!

[StoneNYC]

Awesome Eric. Hope it works well for you!



The app currently supports the following films. There are one or two obvious omissions - Astia, Provia and Portra for example - this is because all my research indicates that reciprocity is of minimal concern with these or I have simply been unable to find useful data.
The Tri-X times the app determines have been found to have some issues in the current release. These have been resolved and times that more accurately reflect Kodak's official data will appear in the next version. Along with a few other enhancements. I just need the time to complete it!


Velvia 50 (unfiltered)
Velvia 50 (with magenta filter)
Velvia 100F
Provia 100F
Ektar
Efke 25/50
Fomapan 100
Fomapan 200
Ilford HP5+
Ilford Delta 100
Ilford Pan-F+
Ilford FP4+
Ilford SFX 200
Ilford XP2
Kodak T-MAX 400
Kodak T-MAX 100
Kodak TRI-X
Kodak PLUS-X
Kodak Tech Pan
Kodak T400 CN
Kodak TMZ

Wait I thought Acros 100 was supported? Has this changed? It's specifically what I use for long exposures because it has such good reciprocity characteristics and use it when I shoot 10 minute to 4 hour exposures... Thanks!

[michael slade]

I guess I am using a different app called 'Reciprocity'. Let me download yours and check it out. Thanks!

EDIT: Oh yes, your app is much better. Well worth the price. Thanks!

[Boinzo]

Wait I thought Acros 100 was supported? Has this changed? It's specifically what I use for long exposures because it has such good reciprocity characteristics and use it when I shoot 10 minute to 4 hour exposures... Thanks!

My understanding is that Acros has virtually no reciprocity up to 2 minutes and was then add 1/2 a stop. Does that sound correct? If so - I will add it in the next release ...
:-)

[StoneNYC]

My understanding is that Acros has virtually no reciprocity up to 2 minutes and was then add 1/2 a stop. Does that sound correct? If so - I will add it in the next release ...
:-)

You are correct that it has no failure for 2 minutes, but I don't know after that, but the PDF for the film as the reciprocity chart in it (all the fuji pdf's seem to have it.

But I'm no good at math so having a chart would be great help after the 2 minute mark, right now I just "guess" lol

[Boinzo]

No worries Stone. Just PM me the chart you have and I'll see if I can do the math and include it in the next version. Be aware though that all reciprocity math after 2 mins is a bit sketchy as a film's characteristics may start to increasingly deviate from the expected math. If that makes sense!

[Eric Bryan]

I used this app yesterday when I was shooting a beach sunset. My stopwatch is in the shop for repairs, so I found the included timer on this app to be super useful.

Just wanted to say again, this is a kick-ass app and I've been sharing it with all my film friend :)

[dperez]

I made a 1 hour and 30 minute exposure on Arista Ultra EDU 100 using the Fomopan 100 settings on this app, worked great!

[welly]

Awesome Eric. Hope it works well for you!



The app currently supports the following films. There are one or two obvious omissions - Astia, Provia and Portra for example - this is because all my research indicates that reciprocity is of minimal concern with these or I have simply been unable to find useful data.
The Tri-X times the app determines have been found to have some issues in the current release. These have been resolved and times that more accurately reflect Kodak's official data will appear in the next version. Along with a few other enhancements. I just need the time to complete it!


Velvia 50 (unfiltered)
Velvia 50 (with magenta filter)
Velvia 100F
Provia 100F
Ektar
Efke 25/50
Fomapan 100
Fomapan 200
Ilford HP5+
Ilford Delta 100
Ilford Pan-F+
Ilford FP4+
Ilford SFX 200
Ilford XP2
Kodak T-MAX 400
Kodak T-MAX 100
Kodak TRI-X
Kodak PLUS-X
Kodak Tech Pan
Kodak T400 CN
Kodak TMZ

I've been shooting with Fomapan 100 for a while now and use RT for my reciprocity calculations. The app reports 1 second exposures for Foma 100 to result to 1 second. However, looking at a few sites, they report Foma 100 at 1 second should be 1.9 seconds.

See:

* http://consumptive.org/technical/Fomapan_100_Schwarzchild_Effect.pdf
* http://www.apug.org/forums/viewpost.php?p=616301

I may try this and get back to you to confirm though!

[Michael W]

I've been shooting with Fomapan 100 for a while now and use RT for my reciprocity calculations. The app reports 1 second exposures for Foma 100 to result to 1 second. However, looking at a few sites, they report Foma 100 at 1 second should be 1.9 seconds.

See:

* http://consumptive.org/technical/Fomapan_100_Schwarzchild_Effect.pdf
* http://www.apug.org/forums/viewpost.php?p=616301

I may try this and get back to you to confirm though!
I just had a look at the Foma data sheet I have as a pdf and it states no correction required up to .5 second. A 1 sec meter should be given twice as much light (so 2 seconds as you say), a 10 sec meter should be multiplied by 8 and a 10 sec meter reading multiplied by 16.
So the app does disagree with the Foma numbers. The question of course is which is more accurate?

[Tony Lakin]

Great idea:cool: wish I could afford an Iphone/pod:(

[StoneNYC]

Great idea:cool: wish I could afford an Iphone/pod:(

Says a guy shooting LF lol

[Eric Bryan]

Says a guy shooting LF lol

Haha I was thinking the same thing :cool:

[Tony Lakin]

I acquired all my LF equipment up until a couple of years ago when I was a practising professional photographer, I also layed down stocks of LF film prior to my retirement, now I have a small pension which will not allow any more large capital purchases, any spare cash goes on materials:p

[StoneNYC]

I acquired all my LF equipment up until a couple of years ago when I was a practising professional photographer, I also layed down stocks of LF film prior to my retirement, now I have a small pension which will not allow any more large capital purchases, any spare cash goes on materials:p

FYI an iPhone is $100 with contract, you can probably afford that, can't you? Or sell/barter for one. If you have a toyo 45A I'll trade for my iPhone ;)

[tenderobject]

Great i will get this app later on. Would you add foma400 soon? Thank you!


Awesome Eric. Hope it works well for you!



The app currently supports the following films. There are one or two obvious omissions - Astia, Provia and Portra for example - this is because all my research indicates that reciprocity is of minimal concern with these or I have simply been unable to find useful data.
The Tri-X times the app determines have been found to have some issues in the current release. These have been resolved and times that more accurately reflect Kodak's official data will appear in the next version. Along with a few other enhancements. I just need the time to complete it!


Velvia 50 (unfiltered)
Velvia 50 (with magenta filter)
Velvia 100F
Provia 100F
Ektar
Efke 25/50
Fomapan 100
Fomapan 200
Ilford HP5+
Ilford Delta 100
Ilford Pan-F+
Ilford FP4+
Ilford SFX 200
Ilford XP2
Kodak T-MAX 400
Kodak T-MAX 100
Kodak TRI-X
Kodak PLUS-X
Kodak Tech Pan
Kodak T400 CN
Kodak TMZ

[davidmarinero]

What a great app! I used to carry a cheat sheet with reciprocity tables and used a calculator to figure out bellows extensions and filter factors. Not anymore! Now what I need are some good gloves that allow using a touchscreen whilst being warm enough for New England's winter ;)

Can anybody confirm whether the reciprocity compensation of Velvia 100F is the same as Velvia 100 (no F)?

[Eric Bryan]

I believe Velvia 100 has a reciprocity time closer to Velvia 50. I treat Velvia 100F as I treat Provia 100F in terms of reciprocity.

Hope that helps!

[Larry Kellogg]

Hello,
First, I bought your app. As a fellow iPhone app developer, I know that is good to hear. ;-)

I don't see Kodak Tri-X 320 in the list of films. This one (http://www.bhphotovideo.com/c/product/243153-USA/Kodak_8416638_TXP_4164_4x5_50.html). Am I missing something? Can I treat 320 the same as 400 in terms of reciprocity?

[Eric Bryan]

What a great app! I used to carry a cheat sheet with reciprocity tables and used a calculator to figure out bellows extensions and filter factors. Not anymore! Now what I need are some good gloves that allow using a touchscreen whilst being warm enough for New England's winter ;)

Can anybody confirm whether the reciprocity compensation of Velvia 100F is the same as Velvia 100 (no F)?

Here's Fuji's data sheet for Velvia 100. You're fine out to a minute of exposure :)

http://www.fujifilm.com/products/professional_films/pdf/velvia_100_datasheet.pdf

[Boinzo]

Hello,
First, I bought your app. As a fellow iPhone app developer, I know that is good to hear. ;-)

I don't see Kodak Tri-X 320 in the list of films. This one (http://www.bhphotovideo.com/c/product/243153-USA/Kodak_8416638_TXP_4164_4x5_50.html). Am I missing something? Can I treat 320 the same as 400 in terms of reciprocity?

Thanks Larry!
As far as I know Tri-X 320 and 400 share the same data-sheet (here (http://www.kodak.com/global/en/professional/support/techPubs/f4017/f4017.pdf)) so you should be fine to select 400 in the app.
All the best!