basing exp/dev techniques on lens being used?

[djkloss]

by that I mean,
has anyone ever experienced a change in contrast in large format lenses so that it might be wise to base their exposure / development technique (time/dilution etc) according to which lens was used?

the reason I'm asking is because I noticed that the other day when I developed 6 sheets together the contrast of the negatives was so much different with the first sheet from the next 5, that I could only assume the lens characteristics. The first, with much contrast, was taken with a Kodak Ektar 127mm and the next a 90mm Ilex-Calumet Wide Field Caltar. I never even considered this to be part of the equation.

Any thoughts / experiences with this? Am I way off base here? I don't think it was reciprocity failure, because the exposures weren't that long and very similar.

Thanks in advance...

Dorothy

[df cardwell]

Absolutely.

There are too many variables to list, it comes down to the charecteristics of a lens,
and can be exaggerated by exposure differences.

Lots of us ancients used a variety of lenses in the studio to manage contrast
without changing development.

Although your Ektar is an old lens, it has fewer air-glass surfaces than the 90,
and inevitably will have higher contrast, as well as transmitting more light to the film.

Coated lenses have simplified our job greatly. When we all shot uncoated lenses,
often the speed of certain lenses was offset by the light scatter within the lenses.
For example, an f/2.8 lens might not transmit any more light than an f/5.6 of a different design.

Good articles can be found by Rudolph Kingslake in old Leica or Graflex manuals.

Test, test, test. Get some Polaroid, while you can, and get a handle on this. Have fun ! You can use it to your advantage.

[djkloss]

Thanks, I'm really enjoying this stuff. And the focusing is getting easier too!

[keithwms]

Dorothy, assuming we are talking only about b&w here, I think my approach would be first to try to equalize the contrast of the lower-contrast lens with a yellow filter (unless of course you like the lower contrast result, which would be a reasonable thing for some subjects). Next, failing that, you might consider rating the film a bit lower (i.e. thus overexposing a bit) when using the lower contrast lens. If that still didn't equalize the results as much as desired, then and only then would I start thinking about lens-specific development.

Yes, you can optimize development per each lens but that approach strikes me as quite far downstream if you are going to be regularly switching lenses. Plus, I simply think that one should eliminate as many stray variables at capture time as possible.

I definitely second the DF's suggestion of checking with polaroid or the fuji instant films.

P.S. Another thing, before thinking too deeply about all this, be sure to eliminate the stray variable that most people take for granted: exposure time. If the lenses are shuttered, have you had your shutters checked?

[Fred Aspen]

Bet it's a slow shutter in the Ektar.

Fred

[djkloss]

yes, b&w - Fomapan100 @ ei50. how would the shutter effect contrast? as for filters, I'm still try to rig something up. There are no threads and I don't have any square filters yet. I'm going to try using my round threaded 77mm filters (you'd have to see the setup).

[Fred Aspen]

A slow shutter will give more density to the neg through overexposure compared to a shutter working properly.

Fred

[keithwms]

P.P.S. Bear in mind that some shutters can be slower than they should be over one range, but faster than they should be over another.

There is no substitute for a good check at all speeds.

[Peter Schrager]

this is a good thread....going from using my trusty Ricoh TLR to a mamiya 7II I needed to REDUCE the develoment time for the mamiya by about 12% to achieve the same contrast level that I had worked out for the Ricoh...i.e. targeted for a grade 3 paper right out of the can...learned this the hard way after exposing 15 rolls on a trip then over developing the mamiya negs...better now than later....the modern lenses have a lot more contrast..plain and simple
Best, Peter

[djkloss]

A slow shutter will give more density to the neg through overexposure compared to a shutter working properly.

Fred

which is similar to 'pulling' which would require less development otherwise resulting in more contrast. makes sense. but I wonder how by much. I would think that a one or two stop difference would be audibly noticeable wouldn't it? at least at slower speeds. maybe not. I know there is a definite slowness in the winter, but I thought the temperature out was warm enough for it to work properly. On the other hand, it is pretty old - and we do tend to slow down a bit after a certain point.

I wonder, how much $ to have a lens cleaned and calibrated. KEH?