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Reciprocity Timer 1.0
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 It is a simple little app I originally made for my own use that I thought others might also get some value from.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 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.
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Re: Reciprocity Timer 1.0
Been hoping for something like this, will download and give it a try.
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It would be useful to know all of the films included.
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The included films are listed in my post. I am also happy to add new films as the maths comes to hand!
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OK. I did not notice that. What I should have said is that I wish it had TMY2!
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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!
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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!
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tmax 100 and 400; Efke 25 and 100; Acros 100 are those I use the most. Looks good.
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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???
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Any chance of adding Velvia 100?
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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?
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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.
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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?
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Re: Reciprocity Timer 1.0
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!
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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.
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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.
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Re: Reciprocity Timer 1.0
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 (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.
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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.
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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.
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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.
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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.
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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?
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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.
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By the way, is the updated version available? I can't find it. Thanks.
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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.
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Glad to see the support. I've just purchased it.
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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
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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 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...
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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...
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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
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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...
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Re: Reciprocity Timer 1.0
Quote:
Originally Posted by
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...
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
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Just happy to have bought your app and support all your good work.
LJS
?Porta 160 and 400?
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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.
Quote:
Originally Posted by
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.
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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....
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thanks a lot for this boinzo, please let us know when apple accepts it!
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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.
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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.
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Boinzo,
Thanks for the App.
One (hopefully not too stupid) question: What is the difference in the Velvia 50 tabs (filtered/unfiltered)?
Thanks.
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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!
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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!
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I am using it on an iPad. Is it hard to "upsize" the app for iPad?
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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!
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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.
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Quote:
Originally Posted by
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.
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
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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.
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Quote:
Originally Posted by
jeroldharter
Good point.
For someone with no Mac skills, I have a lot of ideas.
Hey, you're an Artist, not a coder :)
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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! :)
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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
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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.