Can we talk about "Image Quality"?

[kenn threed]

Hi all,

I like to hear some views on the somewhat nebulous term IQ (Image Quality).

Do you think this is a fixed characteristic of any given camera or sensor?... which doesn't change regardless of light, subject, lens, or settings used?
Or does the "IQ" produced by any camera change for better or worse depending on such things as exposure, color, and dynamic range of the image being captured.

I'm trying to separate the term Image Quality from any measure of skill on the part of the photographer...
as in: The Image Quality of a full-frame DSLR is inherently better than that of a "crop body" or a compact "point and shoot" camera.

I think this might be a different question for prints than it is for web displays, but I'd just be interested to hear any opinions you all have about this.

Kenn

[Jim Poor]

Interesting subject for sure Kenn.

Any given camera will have what I call a maximum image quality. That is, all things perfect, 'this' is the best you get from camera X.

Beyond that, just as lenses have "sweet spots," cameras have strengths and weaknesses.

Some Olympus cameras have wonderful color, but start to get really noisy as low as ISO 800.

My old D300 gave the illusion of more reach due to the crop factor, but was slower in terms of shutter rate and also noisier than the D3.

For example, my current bodies are D3 which are wonderful in low light and have a fast shutter rate making them good for low-light action photography.

When the D3x came out with higher resolution, but slower shutter rate and low light performance that was only good instead of wonderful, I knew that that camera wasn't for me.

The D3 is great for indoor dog sports and great for portraits while the D3x would be marginal for indoor dog sports and WONDERFUL for portraits.

I skipped the D3x and now have a D3s on the way because I could really use the extra low light performance. 90% of what I shoot with the D3 is at ISO 6400 and f/2, so if the D3s can get me to ISO 12,800 and f/2.8 or f4 then I've got more flexibility in lens choices. I also have better (hopefully) performance at ISO 6400 and f/2.

Selecting the correct equipment and getting the most out of it is where the photographer skill sets come into play.

[Marc Mol]

if the D3s can get me to ISO 12,800 and f/2.8 or f4 then I've got more flexibility in lens choices. I also have better (hopefully) performance at ISO 6400 and f/2.


I'll be very interested to know what you think when you get your hands on the D3s Jim. I have the D3 as well and atm, can't justify moving to the D3s, may wait for a D4.
But only if it gives much better high ISO quality & processing speed.

[Jim Poor]

Have you downloaded the sample files for the D3s? They are pretty far ahead of even the D3, but then again we all know how those publicity files work so I hope they stand up when I get my greedy little hands on it.
It is supposed to be delivered tomorrow, but I have a private photo shoot, so I may not be here for it :(

I have two large portrait events this weekend, but the real test will be on the 12th when I have to shoot indoor dog agility at a place that usually forces me to break out the 85mm f/1.4 just to get 1/250 at ISO 6400. It will be nice if I can get to the 200 f/2 or the 70-200 f/2.8 (probably pushing it there).

[Roger Clark]

Kenn,

Image quality is subjective and the bottom line is lighting, composition and subject are more
important than the inherent image quality that a camera delivers. But having said that,
the capabilities of a camera and its sensor can be studied and quantified.

I have done some studies on image quality and I have a model for digital camera image quality. See:
http://www.clarkvision.com/articles/digital.sensor.performance.summary/index.html#AIQ

I call it Apparent Image Quality, AIQ.

(For those familiar with my web site, I have reorganized my articles that were in multiple directories under one directory: http://www.clarkvision.com/articles so if you find a broken link from another site, or a broken bookmark, go the the articles page. All the articles are still there. plus some new ones. If you find a broken link on my site, please let me know.)

Roger

[Jeff Donald]

I've got to agree with Roger. Image Quality is a subjective personal standard used to evaluative a digital file or print for an intended use.

[Charles Glatzer]

Kenn,

Image quality is subjective and the bottom line is lighting, composition and subject are more
important than the inherent image quality that a camera delivers. Roger


Roger,

Wonderfully and succinctly stated. Could not agree more.


Best,

Chas