infrared film query..

[Daniel Taylor]

i have a 4x5 monorail camera and am planning to use infrared for first time. my questions are:
1. is 50- 100 rated iso normal?

2. how many stops do you have to open up to compensate for the effect?

3. how do you focus with large format camera? there are no marking for infrared on this camera.

[Craig Wactor]

1. depends on the film (macophot?)
2. huh?
3. depends on how long the lens is, focus normally, then [from kodak]: try extending the lens by 0.25 percent of its focal length beyond the correct focus for visible light. That is assuming you are using a filter to block most of the visual light. Stopping down also helps.

[Ed K.]

Hi Daniel,

If you're using Maco 820, it is much like FP4 when no filter or a regular red
filter is used in its behavior. If you want the full infrared effect, you need the opaque
filter, and some trial and error. During the day, start with about ISO6 from a visible
light reading - should get you in the ball park. Late afternoon or night don't have much
infrared, so it will be more difficult to get the right exposures. If you have a way to
measure infrared light, great - but a regular light meter won't do it. Maco
is actually a rather nice regular film with no filter at all. It will pick up a little
infrared effect with a deep red - a tad different than regular film - and the
focus shift won't come in to play much if at all.

I shoot Maco and have had good results during the day, with an opaque filter that
gives black skies. As I've shot usually at somewhere between f22 and f45, focus
has not been much of a problem - plenty sharp. I focus without the filter of course,
and then go toward infinity with the image looking sharp instead of stoping my
focus movement just as the image barely gets in focus. Seems to work fine. For
close-up subjects, you'll have to see if somebody here has a more precise method.

Make sure that the light traps are good in your holders, and limit the time they
spend in direct sunlight if you can. So far though, using regular holders in nice
condition, no issues.

The URL for the Kodak tech sheet that suggests focus difference is:
http://www.kodak.com/global/en/professional/support/techPubs/f13/f13.jhtml

[Daniel Taylor]

sorry........here is more info on my lil dilema (haha)
820 maco aura 4x5 b/w infrared, r72 filter and i live in washington state, keep that in mind....as it is a 50-50 crap shot on the weather....some days good some days...well, you get the picture.
what i normally shoot is this.....parks-muncipal or nat'l/state parks. i usually work with b/w or slide film (velvia) when photographing any subject. hope this helps

[Michael S. Briggs]

I don't adjust my focus for IR LF photography and haven't noticed a focus shift. With the variety of modern lenses, I don't think any simple rule could work. Here are two previous discussions:
How do you adjust focus for infrared film? at http://largeformatphotography.info/lfforum/topic/498338.html and focus shift with infrared film at http://www.largeformatphotography.info/lfforum/topic/501706.html.

[Marco Annaratone]

The Maco 820 loses sensibility pretty fast above 820nm. I use an 89B filter that cuts below 650nm, and with a setting of 3ASA (three) I get good exposures under sunny conditions. (One should always add "typically" when statements about IR are made, it always depends on how much IR radiation there is in the scene, of course.) I develop it with Xtol 1+2, 14 minutes at 21C, 30 seconds initial agitation, then once every 30 seconds, long prewash to remove the anti-halo.

In your case (R72) you are shooting within a somewhat narrower windows (720nm-820nm give or take) so you may have to decrease the relative ASA a bit more. It's always a bit of a trial and error but rating the film+filter combination at anything between 1ASA and 3ASA should give you negatives you can work with. And if the weather is overcast you probably do not want to shoot the Maco 820 anyway, I guess.

I do not adjust focus. In my landscape shooting the depth of field takes care of any shift.

Cheers

[Diane Maher]

You can shoot during overcast weather, just keep in mind that you will have to adjust your exposure and you may run into rather long exposure times with an IR filter. I shot some Maco film last November with an 88A filter (which is sensitive starting at around 750 nm). I metered as I usually do, then adjusted my readings for the filter factor, and wound up with 8 or 15 sec exposures with either f/16 or f/22 as the aperture. ISO on the meter was 6. Now it was an overcast day close to Thanksgiving and it was somewhat windy and late afternoon to boot. Here's a link to one of the the pics I took that day. I don't recall whether this is a silver print or a palladium print. There is detail in the tree trunk on the neg, but this print doesn't really show it. dianemaher.fotopic.net/p9564485.html (http://dianemaher.fotopic.net/p9564485.html)

[Daniel Taylor]

hey diane,
really like that shot!! makes me think of time i lived in oklahoma...has really beautiful winters. there was this tree (very similar to this one!!) by a small pond and it really luminated when about late october through mid november for some odd reason, but it reminded me of that. got anymore of that nature??

[Diane Maher]

No not really, Daniel. I needed to go out last year (and get away from my family) and I just happened to have IR loaded in my holders. I should try again though. Sadly, the tree in that picture no longer exists. It was quite rotten inside and fell back in January.

[Daniel Taylor]

sad to hear that...what i really wish is that someone would publish a book for infrared, specifically for large format cameras...i mean the 35mm books are nice, but don't cover shift and swings,as well as the diferent filters and their affects on the film. as well adjustments need to compensate for filter affect as well some recommended exercises to help with using infrared. just a voacl thought....would anyone besides myself buy this book if it were to exist??

[Diane Maher]

The filters used for IR are the same for LF as they are for 35 mm. My main hurdle was getting used to how to treat the Maco IR film. It's much slower than the Kodak IR film and you can't really use any filter beyond a Wratten 87 with it. I shot the Maco in 120 size and took copious notes on what I was doing before moving up to 4x5 & 8x10 IR. If you are looking for some exercises, try Hugh Milsom's book, Infra-Red Photography. However, he really doesn't get into the Maco films all that much, nor does he do LF IR. I don't make any focusing corrections for the IR filter. I take into account the filter factor when I meter. I'm stopping down considerably for my shots and the results are good enough for me.

[Daniel Taylor]

hey diane,
i picked a odd way to get inot infrared..via lf. you'd think i should've start with 35mm or even 120. but seeing as as i don't have mf camera..i guess kinda goes out the window a lil bit!!hehehe! i used to shoot slides and i caught on pretty quick when doing slides...BRACKET! but i have yet to get out do some shots...i musta picked a bad time to start working with infrared here washington....because i can't get a clear day for nothin. i don't know if i mentioned this or not, but the filter i have is a r72. as far as adjusting the camera, i was told told to barely move a hair turn forward to account for the infrared affect. i would most certainly like share any that i get done soon with you....you seem like you really are into this. so i figured i share em with you and everyone else who may be interested as well. i am not going to get my hopes too high just yet, as i really don't have the vaguest clue as to what i am doing right now, so whatever images i may actually get are a learning tool in themselves! but that's all i have for now...hope to hear from you again! thanks!!