How much of a difference does 1/3 a stop make?

[ic-racer]

That Simonds graph looks like a graph for contact-printed photographs. 35mm enlargements have a drop in quality with overexposure, not as steep as the rise in quality with increasing exposure (as you approach the best exposure), but almost immediately after the peak it starts to ‘deteriorate’.

The negative materials were chosen so as to minimize graininess differences among the prints. All negatives of a given scene were made with a fixed camera-lens aperture and all prints were made with a fixed enlarger-lens aperture. -- J. L. Simonds 1961

 

[RalphLambrecht]

It will make precisely 1/3rd of a stop!

No, seriously, it will make very little difference in practical terms. Better to have the error on the side where you get slightly less exposure than the other way, then compensate for the change in the developing stage by perhaps no more than -5%.

An old saying in UK for B&W processing is expose for the shadows and develop for the highlights. That certainly works for me

Then, you want to err on the side of overexposure where the film has far more latitude.

 

[RalphLambrecht]

I am sure the posts here are correct on neg film's latitude and while not wishing to start an argument it does make you wonder if film testing to see how far away from "box speed" exposure you are, is really worthwhile. It suggests that the simplest way to film speed test is take three exposures of the same scene consecutively at box half stop over and a full stop over, use the rest of the film at box speed then develop according to box speed instructions for the developer. Examine the first 3 negs, make 3 prints then make a simple choice of which is the best. End of testing for all except the "real afficionados" of testing. Enjoy the rest of your photography

pentaxuser

that's a good test and you'll be surprised with all the shadow detail you'll get with overexposure.

 

[Old-N-Feeble]

I'm sure everyone here is familiar with the 'rules of thumb': For negative film err toward overexposure; For transparency film err toward underexposure. Of course, it depends on whether one has metered correctly and on the subject matter.

If the exposure is already nearing loss of important detail then yes, 1/3 stop in the wrong direction does make a difference between a great image and a very good one. Once detail is lost it can never be added. If the meter reading is already deep into the toe of a film's lower limit and if that shadow detail is important then we'd better not expose 1/3 stop less. If the reading is already high into the shoulder and that highlight detail is important (usually slide film) then we'd better not expose 1/3 stop more.

Most of us don't work that close to the edge but those who do know this is absolutely true.

 

[Sirius Glass]

A slight under exposure with slides, can provide color saturation.

 

[E. von Hoegh]

I'm sure everyone here is familiar with the 'rules of thumb': For negative film err toward overexposure; For transparency film err toward underexposure. Of course, it depends on whether one has metered correctly and on the subject matter.

If the exposure is already nearing loss of important detail then yes, 1/3 stop in the wrong direction does make a difference between a great image and a very good one. Once detail is lost it can never be added. If the meter reading is already deep into the toe of a film's lower limit and if that shadow detail is important then we'd better not expose 1/3 stop less. If the reading is already high into the shoulder and that highlight detail is important (usually slide film) then we'd better not expose 1/3 stop more.

Most of us don't work that close to the edge but those who do know this is absolutely true.

The scene is Procrustes' bed, the film the hapless wayfarer.

 

[E. von Hoegh]

A slight under exposure with slides, can provide color saturation.

Good for projection.

 

[DREW WILEY]

Yep. Slide shows were either the best or the worst way to spend an evening, depending on whose slides they were! Kodachrome looked good a half stop under. What little that remains today of E6 slide films aren't as amenable.

 

[Doc W]

I am sure the posts here are correct on neg film's latitude and while not wishing to start an argument it does make you wonder if film testing to see how far away from "box speed" exposure you are, is really worthwhile. It suggests that the simplest way to film speed test is take three exposures of the same scene consecutively at box half stop over and a full stop over, use the rest of the film at box speed then develop according to box speed instructions for the developer. Examine the first 3 negs, make 3 prints then make a simple choice of which is the best. End of testing for all except the "real afficionados" of testing. Enjoy the rest of your photography

pentaxuser

Pentax, I think you are mostly right, and for ages, photographers have just opened up a little to get better shadow detail. You would still need to find out your optimum development time but that is not hard to do.