Iso 2500 m9

[adan]

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No action written, because it usually requires fine-tuning to each picture and each lighting situation. The numbers I gave are just the ones that seemed the best balance for this particular picture, as a rough example.

[Guest mc_k]

I have not read other threads on exposure and am trying to reconcile the info in Thorsten and Andy's first posts. Say higher ISO is called for. Which is better and why:

 

1. expose "properly"

2. underexpose 1 stop and push

3. overexpose 1 stop and pull

 

?

 

Is the answer the same for M8 and M9? Is the answer the same for 2 stops?

 

I think this will also answer Melissah's question.

[adan]

The short answer would be 1) expose properly - or 1(a) expose as generously as possible for the scene. (not the same thing as overexposing). Same for either the M8 or M9.

 

What constitutes exposing properly is a debate older than Ansel Adams, who wrote a whole book on the subject and still didn't cover everything.

 

In digital, it usually means making full use of the camera's dynamic range, as determined by a histogram. The only flaw is that the histogram doesn't exist until after the exposure (except in LiveView), so it doesn't help when choosing the exposure unless one does some test shots ahead of time.

 

Below I've posted histograms from three of the jpegs posted on this thread, the OP's, the dog on the sofa, and Ian's daughter. Since these are not the as-shot histograms, they are just a rough guide. But obviously the OP's road shot is very underexposed - most of the image is a spike up against the left side. The dog shot is a bit dark, but that's partly the function of the lighting, and overall it uses the full width of the histogram. The child shot is very generously exposed, with lots of midtones, yet without running off (clipping) the right side.

 

The child histogram would be the ideal, in most cases. This is what is meant by "expose to the right" - i.e. use all of the space available up to, but not past, the right side of the histogram.

 

Since you can't see the histogram before shooting, techniques for getting close to an ideal histogram "blind" would be:

 

> meter a gray card placed in the same lighting as the subject-to-be, after careful testing to check for metering bias - i.e. you may find you really get the most accurate exposure of a gray card by consistently using + or - EV of up to a stop. Again, that is not overexposing or underexposing - it is correcting for a meter that tends to underexpose or overexpose in the first place.

 

> use an incident meter, which is similar to using a gray card (it ignores unusual subject darkness or brightness like white or black walls, etc). Again, it requires up-front testing, because, for example, the best exposure with the camera set to ISO 2500 might require the meter to be set to 1000 or 1600 or 3200 (again, not pushing or pulling, just empirically getting a correct correspondence between the meter ISO and the actual camera sensitivity).

 

> Use Ansel's Zone System technique of metering a shadow area that needs to just barely show detail, and then underexpose 2-4 stops from that reading (depending on the dynamic range of your sensor or film as determined ahead of time by testing) to make that shadow area accurately dark.

 

> No doubt various other metering techniques.

 

You'll note that all of the above assume that you can't trust any meter until you have tested it yourself and determined what corrections, if any, are needed for using that meter in the future. Including both the M8 and M9 built-in meters and autoexposure.

_______________________________

 

A parable for high ISO work. 'Way back when, I did a story on a small auto race track. Very low light - maybe a dozen 250-watt bulbs lighting an area of 2 acres. My meter wouldn't even register. So I just shot wide open (f/1.8-f/2) on HP4 at the minimum shutter speed I needed to stop action (1/60), and then ran the film through undiluted print developer to develop every possible grain of silver exposed.

 

Effective ISO was probably about 8000 - a huge push in those days - a decade or so before TMax/Delta 3200. Most of the negs were still thin and needed printing on grade 5 paper for good separation.

 

Neither I nor Ilford would have used those images to promote the "low-noise" characteristics of HP4 - from that perspective they were terrible. But they told the gritty story of dirt track racing when published.

 

So you do what constitutes "good" technique when possible or required - and you do whatever is necessary to tell the story the rest of the time.

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[noah_addis]

I agree with adan about using the histogram, it can be very valuable. It's tricky though, it will never look ideal in some situations.

 

If you're shooting an area with large areas of one tone, then it may be impossible to get a nice full-looking histogram. Especially if you have, say, a lit subject on a black background.

 

One nice thing about the M9 and M8 (and other cameras may do this too) is that you can zoom in on an area, then push the 'info' button to get a histogram of that particular area of the frame.

 

This feature can be very useful for nailing the exposure on one particular part of the photograph.

 

I'm still a big fan of incident meters as well.

[Jager]

If you're shooting an area with large areas of one tone, then it may be impossible to get a nice full-looking histogram. Especially if you have, say, a lit subject on a black background.

 

 

Exactly. That's an important point to bear in mind. In a scene like the OP, most of the image looks grossly underexposed from a histogram perspective. But that's the way the scene actually was. Most pixels showed no light because... there wasn't any.

 

Just like the exposure meters of yore, one must balance the histogram reading one gets against the human understanding of what the scene is supposed to look like.

 

Alan's explanation is excellent...

[3rdtrick]

I am not offended by the criticism of the photo, it was a grab shot from my truck while on my way home from work. Of course I could have done a manual white balance, used longer exposure, maybe got out of my truck to rest the camera on something solid or even set up a tripod but then I would not need the high iso. Anyway, you all have given a wealth of knowledge and ideas. I am thinking that next time I will compensate 1 stop over exposure, pick my lowest usable shutter speed and use Auto ISO. Hopefully I will not need the highest ISO for all my photos. Here is another "Drive By Shooting" @ 2500 ISO:

 

 

Pete

[Guest mc_k]

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The short answer would be 1) expose properly - or 1(a) expose as generously as possible for the scene. (not the same thing as overexposing)....

 

thank you so much for the detailed answer. I see now that you had actually answered this question in your first posting.

 

Yes I should have said "desired" exposure instead of "proper" exposure. My situation is usually being 1 or 2 stops short of a desired exposure at medium ISO, and I can't go any wider with the lens or increase the exposure time. So I can either bump the ISO now or push later. And they don't seem to be equivalent in experience.

 

It is very helpful to know that others have a personal cutoff at ISO 640 on the M8. I got an r-d1 as a workaround and do shoot at 1600, but the image quality is not completely satisfactory, and I would not say it is 1-1/4 stops "better." I am interested in the M9 because people are saying it is 1-2 stops better than the M8--so I will have to get busy reading the threads on the M9 and exposure in general.

 

Thanks for the book recommendation; I've read his book on Natural Light and also the one on Artificial Light, which have a lot of his exposure techniques, but I will read the big one some day soon. Am glad to hear you think it's a good book to read for digital. Thanks again for the detailed info.

[melissah]

I agree with adan about using the histogram, it can be very valuable. It's tricky though, it will never look ideal in some situations.

 

One nice thing about the M9 and M8 (and other cameras may do this too) is that you can zoom in on an area, then push the 'info' button to get a histogram of that particular area of the frame.

 

This feature can be very useful for nailing the exposure on one particular part of the photograph.

 

I'm still a big fan of incident meters as well.

 

how is it that i didnt know this???

i am so beyond dumb

[melissah]

I am not offended by the criticism of the photo, it was a grab shot from my truck while on my way home from work. Of course I could have done a manual white balance, used longer exposure, maybe got out of my truck to rest the camera on something solid or even set up a tripod but then I would not need the high iso. Anyway, you all have given a wealth of knowledge and ideas. I am thinking that next time I will compensate 1 stop over exposure, pick my lowest usable shutter speed and use Auto ISO. Hopefully I will not need the highest ISO for all my photos. Here is another "Drive By Shooting" @ 2500 ISO:

 

 

Pete

my response was never a crit of you or that photo persay. it was just a crit of a low light situation.

personally im happy you posted a low light drive by image. i believe we've all made those kind of images many times.

i also dont believe you thought of that/those image(s) as serious photographs.

 

so pls take me off your offended list!

best melissa