low contrast

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I am new to large format, I have a orbit 4x5 with a Calter II-E 1:6,8 f210mm lens..I did a few test shots with agfapan 100. it was taken in natural light, half shadow, medium close up of people. It was a very muddy contrast, which is surprising because agfapan is usually pretty snappy.( i shoot alot of agfapan 35mm). What I am i doing wrong? wrong bellows extention? I am going to be doing a series of city landscapes with this camera, any suggestions would be appreciated

-- Deborah Betz (dddbetz@yahoo.com), October 30, 2001


Sounds like at a very minimum a case of underdevelopment, though it could be a combination of underexposure and underdevelopment, depending on whether the negative is thin or not. Is it?

-- Chad Jarvis (cjarvis@nas.edu), October 30, 2001.

might be a camera problem-- a hole in your bellows that is leaking light, possibly?

-- chris jordan (cjordan@yarmuth.com), October 30, 2001.

Give us developer, time, temperature, agitation method, and exposure index, and someone might be able to suggest something.

-- Ed Buffaloe (edb@unblinkingeye.com), October 30, 2001.

I agree with the previous post as per the subject of light leaks. Test your bellows with a point light source from the inside in a darkroom. In you have pin holes, they will be very obvious. I would also add to make sure that your films holders are in good shape and are inserted fully. Pulling the dark slide should be done carefully so as to not pull the holder away from the film backafter in the process. Insert the dark slide squarely to prevent light from leaking past the darkslide flap. If you are light tight and it is not a holder or slide problem, I would look at outdated film or exhausted developer next. Continue to isolate and eliminate a variable at a time or your frustrations will cause you to blame the format and that would be a real shame. Hang in there! Your efforts will be rewarded when you see the results.

-- Michael Kadillak (m.kadillak@home.com), October 30, 2001.

Check your bellows and lens board. I did a whole tour of the South last year, and found out when I got home that my Technika bellows was splitting and pin pointing, although it had be replaced only a few years ago and was little used. Also, light can leak around the lens board if it's not well sealed.

-- Wilhelm (bmitch@home.com), October 30, 2001.

I want to thank everyone for the responses. It is all very helpful. The negative is pretty thin. i had it processed and proofed at a commerical lab . I think I am not getting the concept of the bellows extention and how to adjust the f stop. I am trying to get up to speed as quickly as possible. I am leaving for overseas tommorow and at the last minute decided to take this 4x5 camera, in addtion to my 35mm. I have an unusually opportunity to shoot at an unusually time.

-- Deborah Betz (dddbetz@yahoo.com), October 30, 2001.

If your negatives are underexposed, I would look elsewhere than bellows extension. You don't ordinarily need any bellows exposure adjustment unless you are shooting at very close focus distances. Having your film developed at a lab is probably the biggest variable that you will have to deal with in terms of getting the right contrast (via development time). If you are not sure whether your negatives are underexposed or underdeveloped, I would try to get someone knowledgeable to look at them.

-- Michael Feldman (mfeldman@qwest.net), October 30, 2001.

I personally would not risk an unusual photographic opportunity to unfamiliar equipment. Especially when you've already experienced problems. The advice you'll get on this forum is suberb, but will take time to digest.

-- Henry Friedman (friedlew@worldnet.att.net), October 31, 2001.

It sounds as if you need to add more time to your developing. Start with 15% added time. This will develop your highlights more giving you a punchier negative.

-- Scott Walton (scotlynn@shore.net), October 31, 2001.

I built a small Excel (TM) spreadsheet to calculate bellows compensation. It displays the compensation factor, compensation in stops, and the extension at which the compensation should be applied. I set the compensation increments in 1/3 stops. I can send you the spreadsheet if you wish.

However, because spreadsheets are such an easy way to spread viruses, you can build the spreadsheet yourself (with apologies for my marginal HTML skills):
1 135      
2 135 =A2/25.4 =10^(D2/LOG(2)) 0.0
Now, copy the second row and initialize cell D3, D4, and so on to 1/3 stop values. For example, 0, 0.3, 0.6, 1.0, 1.3, 1.6, etc. For a 135mm lens, for example, this is the table I get:
1 135      
2 135 5 3/8 1.0 0.0
3 150 5 7/8 1.2 0.3
4 166 6 4/8 1.5 0.6
5 191 7 4/8 2.0 1.0
And so on...

-- Bong Munoz (bong@techie.com), November 01, 2001.

Oops, I forgot the formula that's supposed to go in column A starting at row 2: =SQRT(C2*$A$1^2) where $A$1 is the focal length of your lens.

-- Bong Munoz (bong@techie.com), November 01, 2001.

What's that formula for? Have Mercy. Another MIT grad trying to impress the ladies?

-- Andre Noble (andrenoble@yahoo.com), November 04, 2001.

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