D-30 and lenses

[gbjune]

It seems that it is an accepted fact that the D-30 requires lenses that are better than the normal "consumer" type zooms and such.

Why is that ?

Is the quality of the sensor worse than that of film ?

Is it the standards of the people using the D-30 that are higher than whatever standard 35mm film and consumer lenses are capable of anyway, so it's not really a question of whether or not the D-30 needs the lens, but that you should use that lens anyway ?

I've been using a Canon EOS Rebel 2000 with a (cheap) Canon 75-300 III USM (4-5.6) for quite some time and even though people claim it is soft near 300mm, I really haven't had any problems with it and am very happy with the pictures I'm taking.

However, when using my G1, I constantly find that I miss the focusing abilities of my SLR, the viewfinder on the G1 sucks compared to something closer to "the real thing"...

The reason I am asking this is that I am considering (not right now, but maybe some time in the future, when things get calmer in the digital camera world) to get something D-30-like to replace my Canon EOS Rebel 2000 body and hopefully use the same lenses.

The camera body I might be able to justify buying, but I don't think another couple thousand $ is doable. (I would consider myself an amateur photographer).

Insights appreciated.

Geir

[LaptopPop]

No great insights - but you have to get down deep into the optics and film to understand what's going on.

Film all by itself has a higher resolution than the digital sensor in a D30. This makes you think that the D30 would be just fine with a cheaper lens. Also, the D30 only uses the center "sweet spot" of the lenses - sometimes you pay a lot for edge to edge sharpness that isn't used on the D30.

On the other hand, "fast" lenses (2.8 or better) can do a better job at transmitting lots of light to the autofocus sensors - leading to better autofocus performance.

Each lens has a resolving limit. You can think of it as a limit underneath which a point source properly focused would show up as a blurred circle on the sensor. I've seen some calculations which make me think that the sensor in the D30 is smaller than the resolving capabilities on anything but the very expensive lenses. (Of course, I've had some old experience which shows mathematically, that having sensors 1/2 the size of your blur circle or smaller is ideal for getting the most out of an image *after all processing is done*, but oh well.) This would tend to argue in favor of better lenses giving better visible performance -- something which I've seen in looking at sample images.

And that's the bottom line - from the sample images I've seen, the very very expensive lenses seem to not only work better in terms of focus, but they also seem to produce better images on the D30... DARN IT!!! I'd *love* to use cheaper lenses with the same result on a D30. Some calculations would support it, but the images don't.

There really is a reason that many people who can are spending 5 times the cost of the D30 body on a set of lenses - they really do produce better looking images.

-lee-

[afly]

First of all, the D-30 does NOT require anything more than EF-mount. And for achieving decent results the requirements are not any stricter than that.

This leaves the question why so many D-30s have been seen with high-end lenses. I think I can answer that question...

One group of D-30 users are the pros. Actually, they should not be considered at all here. Of course, they have their set of 17-35/2.8, 28-70/2.8, 70-200/2.8 and a big bag full of primes they seldom use, and they have had them many years longer than D-30 has been available. They don't use these lenses because they produce best images possible. They use them because fast autofocus and maximum apertures helps a lot when you have to get the picture in conditions you can not control. Of course, ruggedness and good image quality does not hurt either. For them, D-30 is not reason to get these lenses, but the lenses they already had were the reason to get D-30.

But the amateurs are different. For them, square one is urge to buy digital SLR body. If they have SLR already they most likely have set of lenses cheaper than the high end selection, and since the first body they have dreamed of high end lenses. When someone in this category purchases D-30, the price of D-30 easily justifies spending some more for 'decent' lenses, even if they don't really need them. And once the imminent personal bankruptcy is mentally accepted, it is more or less one and the same what the sum is. After all, D-30 is as expensive as EOS-1v, which is quite much for entry-level model. With body that expensive, it is a lot easier to justify buying equally expensive lenses.

There are some real reasons for getting those high-end lenses. 1) apertures, and 2) they are compatible with teleconverters. 400/5.6 is as big and as heavy as 70-200/2.8 with 2x teleconverter. I think you can guess which package is more limited.

However, I think that with digital body the problems lens may have will be seen easier. Since current CCDs are not good enough to beat film (the fact that CCDs are smaller in area does not change this - yet) the diffenrences must be elsewhere. I'm quite sure it's the ways pictures are looked at. With film, you must either have projector or light table and a loupe, or a quality print or scan. All of these limit the ways of looking the details or rely heavily on the quality of another optical instrument.

And then, how often do you really look the slides you've taken with that 75-300 with, let's say, 10 x quality loupe? Comparing the corners to the center? Yup, I know, not very often. You just check that the focusing is right on or maybe few details. On the other hand you've digital image you can zoom easily beyond pixels and easily compare parts of pictures. I think the conventional way is much more forgiving, since finding something like decreasing sharpness in the corners requires quite a lot of work, but with digital image it is basically effortless when the picture is right.

Biggest image quality improvement one gets with high end lenses is the increased sharpness and falloff at edges. D-30 does not use the full area of 35mm film, which is also reason why there's that 1.6 multiplier for focal lengths. Since D-30 does not use the edges of the lens to anything, bad performance will not be as visible as with 35mm film.

I think that at this point, when digital photography has technically evolved in few years from joke to being almost-there, we have gotten too used to evaluating all the pictures too purely by technical values. It is all just quest of perfect skin tones, finding the distortions, eliminating flare and so on. None of these is required for good photograph. None of these attributes has been available more than few decades, and amazingly good photographs have been taken long before that. I do not denounce modern technology, but I prefer good pictures to technically perfect pictures. Don't forget subject, composition and light.

Ok, that was the sermon of the day. If I offended someone I promise I'll do it again :-)

(If I didn't have the 70-200/2.8, with D-30 I'd probably get the 85/1.8 or 100/2, Especially because lightly used second hand units are easily available for reasonable prices)

[LaptopPop]

For the most part, I'd agree with you.... but...


afly wrote:
First of all, the D-30 does NOT require anything more than EF-mount. And for achieving decent results the requirements are not any stricter than that.


Right. The key word there is "require". The D30 does not "require" the best lenses to function and get *decent* results. However...

afly wrote:
This leaves the question why so many D-30s have been seen with high-end lenses. I think I can answer that question...


The rest of your post has some valid points, but there's one crucial one missing, in my never-to-be-humble opinion.

THE PICTURES LOOK BETTER WITH THE BETTER LENSES. Given two images, side by side, one with cheapo lens and one with super-expensive L glass super lens.... the pictures look better with the better lens. There are people that go on and on about why there "shouldn't" be any visible difference - but there is a visible difference. I tried to explain one theory of why there is a visible difference in my last post.

-lee-

[afly]

LaptopPop wrote:
THE PICTURES LOOK BETTER WITH THE BETTER LENSES. Given two images, side by side, one with cheapo lens and one with super-expensive L glass super lens.... the pictures look better with the better lens. There are people that go on and on about why there "shouldn't" be any visible difference - but there is a visible difference. I tried to explain one theory of why there is a visible difference in my last post.


Yes. there are differences. Aspheric and apochromatic elements with tigher manufacturing tolerances do make difference that is visible from the results.

My point is that D-30 is not special in making these differences visible. Film would show them more clearly, but people using film bodies are not so overly concerned about it. Optical performance of a lens does not degrade by changing it to D-30. If results with film have been satisfactory, they will be satisfactory with D-30.

If the best possible quality was the only target, there's no reason to use other than 8x10 inch field cameras. Everything below that are compromises that produce quality one considers "acceptable". Compromised to be hheaper, easier to use, lighter, and so on. After all, we are mile down that road, so the the step between a L and cheaper-than-L lenses is quite academic. And honestly, I can not recommend anyone risking credit record for that one step.

Uh, looks like I got stuck on that preaching mode again. My humble apologies if I was a bit uncomprehensible in the previous post ;)

[John - NJ]

Pekka:

Thanks for the examples. They prove your points well.

[Torben]

The difference between the 28-135 and the 70-200 is obvious. In my opinion it's mainly a lack of contrast in the 28-135 picture (you did use a lens hood, didn't you?).
I think the reason is better lens coating in the 70-200.

It's possible to get a close match in Photoshop by increasing the contrast and decreasing the lightness and saturation.

[benamen]

I would have to agree!

[mjordan]

Why are you bringing all these old posts up? A few months old is one thing, but several years old? I see you are new, do you have your sort set for oldest first and you don't realize that these posts are so old? If so, change your sort to Newest first and you won't be replying to such old messages.

Mike