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Do some DSLR/brands handle overexposure better?

Paul L

Paul L

coffee lounge for me
My mind still drifts back to the (seemingly) effortless rightness about exposures I used to get with my film gear when shouting outdoors in mid or bright conditions. Nikon F90X, FM2N, F3 or Bronica SQ-Ai. Usually portraits of daughter going about her life, on a bike, in a park, on a horse and so on. Usually slide on Kodak ISO100 to 160.

Last year I think I posted a shot taken with the Olympus E510 (and 14-42 & 40-150 lenses) I chose after giving up the film gear. It was typical of what I get with the E510, the background highlights are consistently overexposed, so are the whites on clothes for example, much more so than I ever had with film and I have tried changin between matrix and centre-weighted metering.

Is that down to the Olympus and do I need to compensate for all outdoor shots with spot metering, external incident metering or exposure compensation? I have to say it's quite a ball-ache having to remember to do so when going between indoor and outdoor and I had hoped to rely on the processing power in the 21st century rather than use it like my old FM2N. In fact, I don't think it responds like my old FM2N.

Is this down to digital sensors and do all the brands suffer this or are some better than others? It is high time for me to either overcome this with settings or abandon the E510 and start again. I would probably veer towards the Pentax K7 if so due to their lens line-up. My biggest disappointment with Oly is that they have not brought out prime lenses as I had hoped.
 
Paul

I'm not proficient enough technically to talk about the subject in any detail but what I've found with the digital cameras I've owned is that they all tended to underestimate there own sensitivity by anything from .3ev to 1ev, once I'd used the camera for a while I'd get a good idea of where I'd leave the exposure compensation.

My Ixus was left .3ev down, my GRD1 was left 1ev down, my GRD2 is left .7ev down, my G1 was spot on, my EP1 is left .7ev down.


I have no idea why they are not calibrated more closely, or maybe I've messed up and am missing something vital which wouldn't surprise me.

Edit: If you already know this and use the histogram then ignore this egg sucking lesson. ;)
 
fundamental difference between CCD and Film - doesn't matter if its a still or moving camera. You can overexpose film but not CCD's (digital clipping). Conversely at the other end, you can put gain into CCD but film runs into trouble when underexposed...

You also generally have more dynamic range with film than you do with digits, which helps as well when it comes to "sort it out in Post"...
 
Thanks to you both. This rings a vague bell. Digital clipping and lack of dynamic range. Hmm, so outdoors, sunny day (out of or behind clouds as both are problems). How do you narrow the dynamic range to have, say, rider and horse properly exposed and still have workable scenery?

I can understand that dialling in compensation can tone down the otherwise highlighted sky or white clothing elelements but not how to address the dynamic range of the scene. It also rightly points to my having no knowledge of how to work with histograms. I confess I have not even gone near them as they represent a squiggly curve of something or other. Shameful. Sounds like that's where to focus attention?
 
i think the only way to compress the dynamic range of a scene would be by physically lighting it...as you are unlikely you have a set of HMI's and generator to hand :), you could try some pop-up reflectors?
 
Hi Paul

First dynamic range, there is a trade off for what you can have terms of contrast (contrast on your cameras settings), on the one hand you can have a sunny day, bright sky and dark subject and get almost every detail without blowing the highlights or losing shadow info if you reduce your contrast setting, but this will give a flatter look from a contrast point of view, you get all the detail but it doesn't always get a natural looking image.

On the other hand, without such large dynamic differences in the frame you can turn the contrast way up and lose some detail at the extremes of the highlights and shadows but get a very sharp look but with hyped colour which of course can be turned down on it's own.

So the trade off is high contrast=narrower dynamic range and low contrast=wider dynamic range. (I think that's right although I now have the sneeking suspicion someones going to correct me)

Then there is the histogram!

I really don't feel qualified to say more than keep the squiggles within the box, ie as the graph rises on the left hand side and falls on the right hand side, try to keep the slopes within the box, play around with the compensation setting and see how the picture fills out on the histogram.
 
I'm not quite sure that you have more dynamic range on film than on digital, the best any negative can do is anything between black and white, it can do no darker, nor brighter. Digital on the other hand can have significantly higher white points, though black is still black.

That's the whole point with RAW, it allows you work with the full dynamic range of the actual scene, rather than the cropped values recovered from a bandwidth limited negative.
 
sq225917 said:
I'm not quite sure that you have more dynamic range on film than on digital, the best any negative can do is anything between black and white, it can do no darker, nor brighter. Digital on the other hand can have significantly higher white points, though black is still black.

That's the whole point with RAW, it allows you work with the full dynamic range of the actual scene, rather than the cropped values recovered from a bandwidth limited negative.
Click to expand...

Sorry, not the case. You are looking at 9 stops with the best pro digital gear, whereas film is more like 13-14 for 35mm and up to 20 in large formats...

You also can't directly compare because the "noise" is different (gets back to the fundamental under/over exposure difference)


RAW formats will not allow you to recover information that wasn't there to start with (unlike clever things that can be done at the development stage with film), and will certainly not stop something that was clipped from being clipped!
 
Flossie said:
Sorry, not the case. You are looking at 9 stops with the best pro digital gear, whereas film is more like 13-14 for 35mm and up to 20 in large formats...
Click to expand...


I don't think film's range increases with size like an electronic sensor (the limits of which are thermal)

I thought film was 8 stops and that was your lot, detail will go up with size though, I could be wrong I suppose.
 
mmm, could be right there about the large formats not being any better. But standard 35mm is definatly at the 12-14 mark (ask any DoP...) and there's other film stock that goes up towards 20 but the fact they are larger format is probably more to do with their application...
 
This also begs the question of what the reviewers think one stop of light actually is.

I mean, take a look at the different review sites for the latest and greatest in digital gear.

One site will have the dynamic range as 8 stops for an slr, another will quote 12 stops for the same camera and another still will say it's 10 stops, an enormous disagreement!

On the DPReview site some of the dynamic range specs actually change a couple of weeks after review!!!

Some of the pro cams with large sensors have different curves in jpeg giving a lower dynamic range than an inexpensive consumer model with bumped up specs so I'm a little suspicious of the reviews.

Might it be the same for film?
 
From my experience with DSLRs and Leica digital rangefinders (limited to Nikon D3, D3X, D3S, D300, Alpha200, Fuji S1 Pro, Fuji S5 Pro and M8/9): Most standard settings err on the side of protecting detail in shadows at the expense of over exposure of highlights. The newer models (M9 and D3S) do protect highlights more effectively. The two Fuji cameras were unusual at the time in protecting overall dynamic range as a priority over ultimate resolution (pixel density). Sadly the Super CCD technology cannot be obtained now in a body which supports Nikon lenses, but the S5 Pro is still remarkable value for money second hand.

Nikon's "cure" for digital blow out is Active "D" Lighting. Basically this forces the camera to underexpose by 1 or more stops, followed by boosting the shadow detail with a tone curve applied to the digital image. Luckily in Nikon Capture NX2 to you can turn this off and adjust the whole exposure back by 1 stop (or more) and protect the highlights manually if you need to.

I don't know what Canon et al do which is similar to the Nikon approach but there must be some setting I guess, albeit not necessarily available on the Oly E510. If you don't have an automatic feature then it is probably best in daylight to set the camera using a spot meter reading from a grey card, calculate an average adjustment from the camera's reading against one from a spot meter, and leave it dialled in. I generally leave my Nikon's on D-lighting normal and the Leicas get set to manual when the subject is back lit anyway.

IIRC negative film is better in terms of latitude to badly set exposure than slide film. I find with slide film such as Velvia 50 or 100 that you often need to boost the exposure by +0.7 ev to avoid having nothing you can extract from the shadows when you scan the developed slide.


cheers
Cliff
 
Flossie said:
Sorry, not the case. You are looking at 9 stops with the best pro digital gear, whereas film is more like 13-14 for 35mm and up to 20 in large formats
Click to expand...

20 stops is a huge range. If you start at root 2 as the first stop (F1.4) that would imply a lens with stops of:

1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32,44.8, 64, 89.6, 128, 180, 256, 512, 716

At F716, the aperture's circular area on a 50mm lens would be about 0.004mm^2 (versus 1963mm^2 at F1.0)

It would take some special film to resolve anything at all with F1.4 and F716 apertures for the same shutter speed.
 
look up Kodak Tmax 400 film if you don't believe me... it is quite silly what it can do used right... o_O
 
People on the LF forum seem to be able to get 18 stops with a careful workflow and someone says that 22 stops have been claimed by Kodak in their lab.
 
Patrick Dixon said:
People on the LF forum seem to be able to get 18 stops with a careful workflow and someone says that 22 stops have been claimed by Kodak in their lab.
Click to expand...

Do you mean in the same photo on the same bit of film? I would say that is impossible.

Stops relate to the area of the aperture which clearly has a proportional relationship to the amount of light falling on the film/sensor for a given amount of ambient light ouside the camera. The same film (eg TMAX3200) may very well be capable of producing something from F1.4 to F64 and beyone provided that the development is controlled based on the amount of light which actually hit the film. I am not convinced at all that 22 stops could be registered on one piece of film at the same time and developed in one process. (even if the single piece of film is hit from more than one lens/aperture)

Cliff
 
or, quoting someone from the photo forum:

"What you mean with 22 stops is that by exposing TMX with different light intensities varying over a range of 2^22 fold, you get densities that are measurably different."

I would equate that more with the fact than a Nikon D3S can shoot at anything from ISO 100 to ISO 102400 without you phyiscally changing the sensor. It does not mean that at ISO 3200 you will get the same light doing the same thing on the final image at all sensitivities, F-stops and shutter speeds.
 
Pentaxes naturally expose to the left of the histogram. There's no danger of clipping at the highlight end. In fact, for a lot of people, they've slightly overdone the compensation, and a lot of people dial in a +0.3(ish) EV exposure compensation and still don't clip the highlights. I think the Pentax reasoning is that it's much easier to recover shadow detail than recover non-existent highlight detail from overexposure.

It does mean that right out of the box the images can look a little dim/flat.
 
Yes, I think histograms are a Eureka moment for me, you have probably using them since their advent. Knuckles firmly wrapped, I shall now spend my time deducing if the E510 can be made to give me the family shots I try for or whether a Nikon D90 or Pentax K7 have a techical advantage in their 1 or 2 generations more recent development that the E510 can't compete with.
 
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