Digital; am I missing something here?

[art_karr]

After 40 y of shooting film, I started messing with a digital

camera; just for the fun. I have only used one; a Nikon. It actually

works well and produces good 11 x 14's. My question deals with

exposure latitude. It seems more narrow than the most

demanding slide film. I work in PS 7.0 and can fix it to some

extent. Still, I haven't heard much discussion of the matter.

 

This is a Nikon 5000 [hey for a zoom lens, it has less flair than

my Leitz lenses; not bad]. I am not going to buy anthing that

costs more until they quit changing models every 3 months. ;,).

 

Art

[gannet___]

Which just goes to show you that digital image quality is not merely a matter of raw pixel count. :)

 

Image quality from digital cameras will continue to improve long after the pixel count is "enough". Even with the new Kodak (yay!), we ain't seen nuthin yet. Expect the rapid pace of change to continue for some time, imo.

[hal_bissinger]

Duno. We have people here who have said that the dynamic range of digital surpasses film. All I ever see are blown out highlights. Go figure.

[gwilburn]

Art, I picked up a Canon G2 this year and have shot lots of images with it. It's fun, convenient and the image quality is surprisingly good. But like you, I've noticed that dynamic range is limited. This may not be a factor with larger sensors, such as those on the Canon D-30 and D-60 but it's a known problem for consumer level digitals.

 

I have been shooting a lot of 35mm film in parallel and there's no comparison in terms of latitude. Film is far more generous and forgiving than (consumer) digital, in my experience.

[art_karr]

Gene:

 

You could be correct; I am the first to admit that I don't keep up

with digital technology in cameras [i am used to Leica, Nikon,

Hasselblad and the 'HOF"]. Still, from what I have read, the

sensor on my 5 Mp p&s is the same size as the more expensive

cameras.

 

I don't know the differences. I just know it lacks exposure latitude.

I can live with it, but I just wondered if this is normal; and if not,

why is no one discussing it. Bob post's here; maybe he can

comment.

 

Art

[scott_eaton]

10 stops of lattitude is typical for better digital sensors. Depends on how it's calibrated....and this is a problem with lower end digital cameras that I certainly agree with. Consumer print films cause the same problem compared to professional print films, and I've fought that battle to the point of exhaustion.

 

How many stops is slide film capable of? Mmmm....less than 10.

[gwilburn]

Art, the response I got on this dynamic range issue at www.dpreview.com, which is a good digital site, is "expose for the highlights, post-process for the shadows". Meaning, don't let the highlights blow (similar to slide film here). There tends to be more detail in the shadows than appears at first. With a little extra photoshop work, they can be brought out.

 

I'd say digital has a similar latitude to certain color slide films and some of the same issues (consumer digital has nowhere the dynamic range of color neg film or a B&W film like Tri-X). The biggest challenge I have is highlights. I watch the histogram on my shooting for overexposed hilights and frequently have to reshoot by adjusting down the exposure compensation by 1/3 to 2/3 stop (sometimes a full stop). This can be fiddly, but the good news is that I can adjust on the spot. Once I get it right for a particular lighting condition, I can usually shoot the rest of my shots with the same setting.

 

Not really a gripe -- the tools are provided -- just a different way of working. As I said, I have fun with digital, but to be honest, it makes me really appreciate film photography. That's why I do both.

[rainer_viertlb_ck]

allways happens the same with digital signals...( in music recordings happens the same). you have more space overall to record your signal, but if you come over the limit.....it cuts the signal promptly and for 100%. conventional film is compressing the signal in its end of the range...therefore it works softer in the ends of its range. this effect is stronger on negatives...( where you nearly cannot overexpose the lights...) but the same effect happens on slides too.

[scott_eaton]

The highlight rolloff that occurs with film is certainly more pleasing than the 'halt and catch fire' that quite often occurs when digital capture hits its wall.

 

Regardless, you're dreaming if you think more popular slide films can keep up with even cheap digital cameras in terms of dynamic range. The flip side of that coin in photographic terms is obviously who cares what the numbers say - it's a pleasing image that counts.

 

This in one factor that needs to be measured and evaluated when comparisons between digital cameras are made. Less emphasis on stupid pixel count and more the quality of those pixels. This can be fixed a good deal in software, so the more attention is brought to the issue the more likley we'll see it fixed in even cheaper cameras. This is what happens when you only evaluate digital cameras on the basis of reflective test targets in the lab.

[gwilburn]

<p>Art, further to this topic, there's a discussion on the Leica forum that contains links to good reference material on why there's a difference between the pixels in a comsumer level digital and the professional models.<p>

 

<p>Here's the link to the <a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=003qmm">discussion</a></p>

[richard_milner2]

This week's Amateur Photography (UK) magazine has a feature comparing digital with MF and 35mm film.

 

The feature was done by tripodding an MF camera (Mamiya 645AF-D) and using the Kodak DCS Pro Back 645M, and Fuji Provia 100F film. The author shot 35mm stuff on Provia 100F with a Nikon FM2.

 

The author says the exposure latitude of the digital capture was superior to the film. He was able to rescue digital exposures of +2EV using software. The quality was not as good as the spot-on exposure, but it was acceptable for some purposes.

 

It's an interesting article, well worth a read. I'm not going to put everything on here, though.

 

Mind you, this particular digital back costs nearly 12,000 UKP, without a camera to put it on.

[art_karr]

Gene:

 

Thanks for the link. I had alread read it. At work, I have a Nikon

D1X [i think that is correct; it came with the microscope package

and has a wide angle zoom]. It works ok on the scope but has

the same problem in real life.

 

What I have been doing with the 5000 is using manual exposure

[no easy task on these things], exposing for the highlights and

pulling out detail from the shadows with PS. You can get good

prints but not when the exposure range is too large. I suspect

that the over $10,000 US backs work better, but I have now way

of knowing. ;<)

 

Art

[pphaneuf]

I agree with Scott on that.

 

I think latitude and noise can be easily put under control using larger sensor photo-sites. Witness the Canon EOS-1D, with its lower pixel count and massively larger sensor (well, there there are full-size sensors, but bear with me), giving you some of the largest photo-sites out there.

 

The idea is that if you have a very small photo-site, it could receive something like zero, one or maybe two photons at the darker end of things. Two photons is the *double* of one. A photo-site that would be 10 times larger would receive 4, 5 or maybe 6 photons for the same exposure. More detail, as 6 is only 20% more than 5. Less contrast, more latitude, less noise (as noise is the results of magnification of signal difference through gain/amplification).

 

Now, they made cameras with larger sensors and accordingly increased pixel count. I wish Canon would make a "D90" that would have that full-frame CMOS sensor, but only have 6 megapixels. That would be one ass kicking camera!

[art_karr]

Pierre:

 

You could be correct. This wasn't meant to be a thread about film

vs digital. It was meant to deal with practical solutions to deal

with the short-comings of digital [years of experience have taught

me how to overcome the shortcomings of film]. I have a good

idea how the sensors work. Just got back from Cali last week

where I talked to friends who work at designing sensors [not for

cameras, but the principle is the same; when young I was an

engineer; gave it up for lent]. My impression is that the people

who design these sensors are not people who do everyday

photography. If they are, they must not be much better than me.

;<)

 

I am doing this for fun; but I have accepted the challenge they

present. Just wanted to know your experience and how you have

overcome the limitations.

 

Art

[pphaneuf]

Ok. I'd say that you should overexpose rather than underexpose. If the camera has a 48 bit per pixel mode (usually called RAW or TIFF, if there's any), then overexposing a bit (to limit the noise in the darker areas) and playing a bit with the levels (allowed by the higher bits per pixel) should be the best solution.

 

Using the lowest possible ISO should be pretty obvious, of course (to limit the amount of gain).

 

One of my friend told be he used some slight despeckle filter for the worst offenders, but I'd say you're pretty much screwed at that level.

 

Basically, yes, they have very little latitude, and you can only try to hide it, and I'd say that a cleanly blown out area is better than having a noisy dark area, if I had to pick. Pay attention to contrast. Meter carefully (like you would for slide film). Etc...

[pphaneuf]

By the way Art, I just reviewed my first posting on this thread, I didn't mention film at all!

 

I was comparing those very nice pro DSLRs with the crummier amateur stuff.

 

I'd put my barrier for entry for a digital camera at the Canon D30 level (or whatever equivalent other companies have, I've got a Canon system, so that what I look out for). Anything less, I'd rather have a film camera.

 

It gets a bit torny at the Canon G2 or Olympus E-20 levels, you might be less picky than I am, but I wouldn't get one of these. Maybe I'd replace my trusty little Olympus Stylus Epic point & shoot with a Canon S-serie maybe...

[art_karr]

Pierre:

 

Danke; but in addition, I did not mean this to become a

Nikon-Canon discussion. When I have used 35 mm, I have used

Leica RF or Nikon. Started with a IIIF and then an M3 in the late

50's when I was in grade school. Still have them. When I started

using an SLR in the early 60's, I chose Nikon cause you could

get it fixed in any podunk town in the world; like Paris. Doesn't

mean I think that Canon is worse. [Remember this isn't a

discussion about French Culture versus real Culture; ;<)].

 

Just wondered what tricks others were using. For me this is just

for fun.

 

Art

[gwilburn]

<p><i>Just wondered what tricks others were using. For me this is just for fun.</i></p>

 

<p>Art there is one trick you can try. Instead of shooting your digital at the lowest ISO rating (the normal recommendation), select a high ISO for very contrasty scenes, within the bounds of your camera's exposure capability. This, according to some items I've read, results in greater dynamic range being captured, at the expense of additional noise. Remove the noise during post processing with a product such as Neat Image.</p>

 

<p>This may not be a preferred day-to-day process, but it's worth experimenting with and keeping in the tricks bag if it works for you.</p>

[john.mathieson]

Instead of shooting your digital at the lowest ISO rating (the normal recommendation), select a high ISO for very contrasty scenes, within the bounds of your camera's exposure capability.

++++++++++++++++++++++++++++

 

What do you suggest - 1000+?

[gwilburn]

<p><i>What do you suggest - 1000+?</i></p>

 

<p>It depends on your camera. My Canon G2 has ISO 50, 100, 200, 400. I sometimes use 200 or 400 for very contrasty scenes. The G2 has a min aperture of f8, which limits how high I can go in bright light.</p>