View Full Version : Relationship between digital and analog exposure

1-Sep-2010, 14:35
So, it's been several decades since I've shot film before my recent foray into 4x5, which many of you have helped me with. I've gotten a bit lazy in the meantime, since most digital cameras have such good metering.

Here is the question: I long ago sold my spot meter and copy of The Negative, though I'm still familiar with the zone system. I do still have my seconic incident meter. It's been working flawlessly for when the light is hitting the subject directly. Simply meter the light, set the shutter and aperture and fire away.

But what about when the light is more complicated, say shooting into the sun at sunset where it is skimming across the surface of the subject (road, forest, etc). If I were to bring a point and shoot digital camera, set the iso to the film's iso would the image/histogram give me a rough approximation of what the neg will look like? I could get a spot meter and follow Ansel's system, but I'd rather save the money.

I have a feeling that it would be close, but would the tonal range be the same? PS, am shooting portra 160nc

Lynn Jones
1-Sep-2010, 16:04
In sunsets, read directly into the sun and bracket from there. In this case you actually want the sun's detail.

In other landscape situations, take a normal reading for frontal lighting. For side light increase by 1 f stop, in back light increase by 2 stops. Bracket from there until you go ahead and get a meter that includes reflected light spot readings.


Jay Decker
3-Sep-2010, 08:17
Digital cameras are excellent light meters. I frequently take my DSLR when shooting LF. With the ISO set to the film speed and set aperture priority program mode, get happy with the DSLR exposure and then apply the exposure information in the LF shot. It works great!

A couple considerations:

1) More Stuff to Distract You from the Subject: I shoot 8x10 primarily, so I'm hauling a lot of equipment already and addition of the DSLR is not a major logistical consideration. However, I find the more I have to monkey with when shooting, like the DSLR, the more my attention is distracted from the subject I'm photographing. Distraction from your subject is bad. So, I use a light meter when I can not do anything about the lighting. Ansel might roll over in grave if he heard this, but I usually just set the exposure based on a zone III reading and shoot it.

2) Use the DSLR to Set Your Lighting: If you can adjust the lighting, use the DSLR to set your lighting and then shoot it in film. I do this in the field and my home studio. One of the things that it encourages me to do is to experiment with lighting and avoid getting in a rut where I use the same lighting, because I don't want experiment on film, have the experiment fail, and then loose both a photograph of the subject and effort involved in shooting with LF film.

3-Sep-2010, 08:52
As a general light meter, a digicam works fine. But use them to read a particular scene/zone in terms of exposure value/camera settings; your histogram won't factor in development of your film (for b/w) or the characteristics of your film which are different than your digital sensor (for color and b/w), so an an overall expression of what you'll see on film, I see little value in it.

But if I set my compact digi on spotmetering and get the exposure I need for my EI in a paticular zone, it's good to go.

3-Sep-2010, 10:30
Excellent advice. Thanks everyone.

3-Sep-2010, 12:12
I do not have a spot meter, I use a compact digital camera as my only light meter. I find it to work very good, which has been most apparent when shooting slide film in 6x6/6x9. With large format I shoot negative which is more forgiving.

I use it in manual mode and have to keep in mind the limited dynamic range, tone curve of the JPEGs as well as the properties of the film Im using, reciprocity failure etc. I do not just put it in auto and expect it to figure out what I want :) I want to try the zone system and spot metering someday, but spot meters are costly/bulky, and Im getting pretty comfortable with the digital camera metering...

3-Sep-2010, 13:03
Most digital cameras do not perform at the indicated ISO. Typically at ISO100, a digital camera will actually be shooting at ISO80 or ISO64, though this compensation is integrated with the metering system. This may not matter if you are shooting B&W film or color negative, but with slide film, I found it to be very difficult (and expensive) to overcome in tricky lighting. You're asking about shooting landscapes, and for this type of photography, I think a spotmeter will allow you to calculate exposure more easily.

Frank Petronio
3-Sep-2010, 13:22
I think it's silly not to use one, but many people are mired in their habits -- and more power to them... no insult intended against those curmudgeony old bastards, I sincerely mean it ;-) A DSLR is such a powerful and useful tool for large format photography that I think they are being unnecessarily idealistic, like a Mennonite Horse & Buggy driving at night without those sinful "modern" reflectors.

While I don't develop my film per the Zone System anymore, I used it for over 20 years, mostly with my trusty Pentax Digital Spotmeter. But now I get better results checking the Histrogram on my digital -- I just set the ISO to match my film, set the lens at f/5.6 or f/8, adjust the exposure until I get what I want -- and go with it. And yes you still have to compensate for filters, bellows factor, extreme lights and darks, etc. but for the vast majority of the photos I do, WISYWIG.

I'll shoot an Instant Film too sometimes, usually the DSLR and Instant agree. If I felt my negs were too under or over consistently then I'd adjust my film's ISO rating. So far it hasn't been an issue.

If I want to get anal, I can aways use the spot meter on the dslr with a longer lens, but I've never felt the need. I still think the Pentax Spot Meter is the best of the lot but I sold mine. In fact, I went out and bought another after a year without just to see if I was missing anything. And I wasn't, so I flipped that one too.

So go ahead, set the camera on Aperture Priority and adjust the exposure compensation to suit - let the Matrix metering handle it if you like. Of course I use Nikons over Canons, so maybe that is why I get decent exposures.