So, for instance, the Sigma 180 macro goes to F32, I hear what you are saying about diffraction, but is that a function of the CMOS sensors detection physics, (as opposed to film) or is it a function of the lens?
The 10D does great at iso 100 for long exposures, so I figure why not take advantage of this and get some shots where everything is in focus. Yes the reason I want the high F-stop is for riteous depth of field. Unfortunately physics sets some uncomfortable limits. There is no way with conventional opticsĭepending on why you want f28 (DOF or exposure) you can get around That is only because they aren't diffraction limited even at f8).Īt f28, you are well over 3x the size of a pixel with theĭiffraction effects. (Some lens may still improve after f8 if they are bad enough but Larger than the size of a pixel on this camera from about f8 on. It turns out that diffraction effects start to be
Diffraction effects depend proportionately I'm working on a review of the 300/4L IS for my site, but that's going to take some time. On a budget, I'd look into the 85/1.8 for portraits, or the 35/2 for a "normal" lens. then there are lenses like 200/1.8L, 300/2.8L, 300/4L, 400/2.8L that are as sharp wide-open as they are at f/8. The 85/1.2L and 85/1.8 should be fantastic at big apertures, as is the 135/2L and the 35/2 and 35/1.4L. which is kind of slow.Ī lot of the primes. The f/3.5 macro version? I would think this would be great wide-open. The dreamy effect disappears as you stop the lens down, and the sharpness you get for it just isn't worth the trade-off. It isn't tack sharp at f/1.4, but it's more than acceptably sharp there. Mine takes on this gorgeous dreamly look at f/1.4, where out of focus highlights in the background just sing, and any highlights anywhere near your subject just hug and caress that subject. With that, unfortunately physics sets some uncomfortable limits. There is no way with conventional optics around this limitation.ĭepending on why you want f28 (DOF or exposure) you can get around it by using ND filters. (Some lens may still improve after f8 if they are bad enough but that is only because they aren't diffraction limited even at f8).Īt f28, you are well over 3x the size of a pixel with the diffraction effects. It turns out that diffraction effects start to be larger than the size of a pixel on this camera from about f8 on. Diffraction effects depend proportionately upon f-stop. Does Canon or Sigma make anything that really Have a sweet spot range of F stops, and my own experience so far Many of the reviews I am reading indicate that these lenses tend to I am hoping to get the 70-200 L with help from SantaĬan anyone reccomend a lens wich does well at really high f-stops OK so Ive already dropped some $$$ on a stable o lensesĥ0mm 1.8 MK1 (which I may sell if anyone is interested) It needs to be a real Macro Lens and not just a lens with a "macro focus" range. Macro's are often shot as large F-numbers due to the very short DoF, thus it would be more of a design requirement to work as well as possible at small apertures with a lens designed for Macros (such as a Canon or Sigma 100F2.8 Macro). First of all, optical physics will cause you problems as you stop down due to an effect known as diffraction (the bending of light going through a slit - why a pinhole camera works).