DoF, speed and format size

[pmkierst]

That might rule out more than slightly wide angle digital LF with traditional LF lenses, though the new digitally oriented LF lenses might help.

As far as I can tell, these are largely lenses which sacrifice coverage (most won't cover 4x5) in favour of resolution. Traditional LF lenses aren't the greatest in absolute resolution, which presents a problem when using a small digital back. I believe these lenses all have the nodal point in the traditional place so they will still suffer extreme angles of incidence.

There are wide-angle designs (reversed telephoto's, as it were) which have the nodal point behind the lens, giving a smaller angle of incidence. They seem extremely rare.

I would also take issue with the idea that IS doesn't help wide open; I have shot wide open with a 300 and 500 many many times and been very thankful for the IS, even on a tripod. Shoot wildlife at dusk and you will quickly see what I mean.

[Ray]

  My comment about IS not helping so much wide open referred to the IS zooms, which are typically about a stop slower wide open (f/5.6 at the tele. end) than comparable non-IS zooms, so that the longer usable exposure times and smaller apertures somewhat balance out.

BJL,
I believe the Canon IS system gives 2 stops of latitude and the later developments of this system, 3 stops. Some lenses also allow the use of IS with tripod and I think all IS lenses would allow use of IS with tripod on a windy day when there's some movement for the IS to work on.

With IS, the Canon 100-400 F5.6 effectively becomes an F 2.8 zoom. However, as you point out, in situations where the subject is moving jerkily (snapping crocodiles at the zoo, Kung Foo demonstrations etc), there's no substitue for the faster shutter speed that F2.8 can provide.

I think in general when trying to decide on a camera system, one has to look at the whole system including the range of lenses available. The Olypus E-1 has a lot going for it, but first indications are the sensor is simply not good enough to do justice to the fine lenses.

I'm not aware of any independent tests of the Olympus lenses but that MTF chart of the 300mm F2.8 on the dpreview site is sure impressive.  Could this be the best lens in the world?   If one can trust the accuracy of those charts (a big if) this lens has about the same performance at 60 lp/mm as the finest lens Photodo has ever tested at 40 lp/mm (the Canon 200/1.8L).

If my interpretation is correct, the Olympus 300mm F2.8 will outresolve any sensor currently available at any cost, including Olympus' own 4/3rds sensor.

[pmkierst]

As Ray alludes to, the later generations of IS can be used on tripod and can even combat mirror slap somewhat. However, my real us is on a tripod but not locked down, sometimes on iffy ground, sometimes in the wind. This is the reality of wildlife photography, which I am not great at but striving to get better. Under these conditions (even with a Wimberly head) and at dusk -- when the animals tend to be active -- IS is wonderful. To be able to track and shoot a deer with a 300/2.8+1.4 @ ISO 400 wide open at 1/45s on a loose tripod head would not come out well without IS, particularly when you have your tripod on iffy ground. I have done this and the sharpness is excellent.

To answer the very original question: I think that wildlife (and possibly sports) would be of the greatest benefit from small sensors. Smaller lenses for the same magnification would be wonderful. More DoF would be wonderful; when you must shoot wide open and higher ISO in an attempt to get enough light, you would really appreciate any speed you can get. I can imagine a 100/1.4 lens on a very small format camera (say 3x crop) might be the dream of wildlife photographers; the front element would still be quite a bit smaller then a 300/2.8 yet it would be significantly faster and probably have somewhere near the same DoF (just a guess though). If the lens was designed for a very small image circle, the resolution should be very good. I think getting noise levels low enough would be a significant problem.

On the Olympus lens: Comparing absolute resolution is very poor way to go about comparing lenses if image circle is not taken into account. If you looked at an 8x10 lens, its resolution would be terrible. Does that make it a bad lens? Of course not since you can contact print for a 8x10; the lens resolution is essentially the print resolution. For sure, when it comes to resolution, only resolution on the final print can really be considered.

[Ray]

On the Olympus lens: Comparing absolute resolution is very poor way to go about comparing lenses if image circle is not taken into account. If you looked at an 8x10 lens, its resolution would be terrible. Does that make it a bad lens? Of course not since you can contact print for a 8x10; the lens resolution is essentially the print resolution. For sure, when it comes to resolution, only resolution on the final print can really be considered.

Absolutely true. But we ARE taking image circle into account, or more specifically sensor size, since image circle does not in itself determine focal length. (Anyone wish to contest that?    )

If the Olympus lenses have an MTF at 60 lp/mm that is equal to the best Canon 35mm lenses at 40 lp/mm (MTF 60-70%), then for resolution purposes, that effectively boosts the size of the sensor by 50% in each direction. What was an active 17.4x13.1mm sensor becomes equivalent to a 26.1x20.4mm sensor coupled to the best of the Canon lenses.

Still not as good as 35mm could be, but better than the 22x15mm sensor of the 10D could ever be with current Canon lenses. Trouble is, the E-1 sensor does not have the capability to take advantage of this increased resolution. One can only hope that future models will.

[BJL]

Sensor stabilisation as an alternative to IS/VR lenses?

   A news story at the Popular Photography web site
http://www.popphoto.com/article....mber=11
suggests that DSLR makers other than Canon and Nikon are aiming at using "sensor stabilization" to mitigate the effects of camera motion, instead of doing it in the lenses. That is, what Minolta does in the 2/3" (11mm) format A1, but with the challenge of doing it with far larger sensors.
   Minolta by the way is said to be one of those other DSLR makers soon. There are some other fun rumours there too.

[victoraberdeen]

Sensor stabilisation - this could be done in software, no need for any battery wasting then!

[BJL]

Ray,

   there is an idea: view camera style rear motions, shift in particular, by moving the sensor around, as a cheaper alternative to using a far bigger sensor and cropping. Perfect when using 35mm format lenses with an APS format sensor since the bigger image circle is certainly there.
   One limitation would be keeping the angle of incidence of light on the sensor from being too far off-perpendicular to avoid vignetting, or "shading" as Olympus now calls it; but software "shading correction" could add some latitude there. (I have seen about 15 degrees as the angle of incidence limit for typical current sensors with microlenses; there is a bit more latitude if microlenses are not used.)

   About Canon moving to true APS-C (1.4x crop), I have wondered if they might do that as a bit of one-upmanship, now that they have had the opportunity to let all the competition commit to a size. However, they seem to be very happy with the cost advantages and such of having a slightly smaller sensor and pixel size in their lower level models than the "near APS" competition and yet still having a reputation for lower noise, contrary to theoretical predictions of the opposite for smaller pixels. (*)

   The apparently imminent successor to the 1D might be very revealing about Canon's sensor size plans.


(*) Never mind that this seems not to be true and that instead, the 6MP "APS" DSLR's look about "equally very good" for measured noise, except the S2 which looks even better. I conclude this by comparing multiple noise tests on the 10D, D100, *-ist D and S2 in reviews at DPReview and noting fluctuations that can rate one camera slighty better than another in one test, slightly worse in the next.

[Ray]

The only problem with a moving sensor would be accurately depicting the sensor position in the viewfinder

If you're right then we're home and dry. I don't see this as a major problem. I envisage a large, bright 36mmx36mm viewfinder with the sensor showing as a matte or mask. The matte would change format and size as appropriate, according to the camera setting for the position of the sensor or the resulting stitched image format. Mattes are always useful for composing the image. The choices would be 36x36; 32x32; 36x22; 22x15 dead centre and 22x15 in a number of positions for 'shift' purposes.

I think major problems might be (a) the more oblique angle of light the sensor would be subject to in certain positions (as suggested by BJL - I didn't think of that   ) and ( dampening the sensor immediately after changing positions so one doesn't get a 'lack of MLU' effect.

If these problems could be solved, such a system would be a real beauty.