"Icoz, Evrim" wrote: > > I assembled quite a few lenses, and will get rid of some, but before I do, I > want to test them. > > The lenses are: Canon : 28-135 IS, 28-105 USM, 70-200 F4 L, 50mm 1.8 > Tokina 28-80 2.8 ATX PRo, Vivitar 100mm, Tokoina 19-35mm (2nd gen.), Zenitar > fisheye.... > > I will get rid of either the Tokina, or one of the Canon's...
Well, besides testing, I'd think it would be reasonable to get rid of the 28-105. It's certainly a good lens, but you still have the 28-135 - with IS - and the Tokina 28-80/2.8 - with the f/2.8 aperture. Both, IS and f/2.8 can serve different purposes, so there is a reason to stick to them. > > So can you give me some pointers to testing? i will try to test overlapping > points, like 28mm, 35mm, 50mm, 70mm, > and wide open, f5.6, f8, and f16, f22. Redundant? I'd replace f/22 with f/11, at f/22 there's already quite a bit of diffraction anyway. > > Also what film would you recommend? A slow slide film, maybe Fuji Velvia or Provia 100F. > > Tripod on a calm day. How about the target/ What shall I use? I've done a test a while ago, so you might as well avoid my mistakes. ;-) I don't think, test charts are a good thing to use. They are usually quite small and you would have to shoot from a quite short distance. If you use your lenses mainly at that distance range, this is ok. It may be a good idea anyway, to shoot the kind of pictures you normally shoot. You may not be able to come up with resolution in lp/mm afterwards, but you know what to expect in everyday use. And most scenes have all levels of detail to look for with a good loupe on a light table afterwards. Tripod�, cable/remote release, mirror lockup (if available). If you can't resist to shoot test targets (I couldn't), focusing can be a problem. A viewfinder magnifier can help with this. AF is not accurate enough to get the best possible out of your lenses. Also, keep in mind that a lack of sharpness in the corners may just indicate a curved field and doesn't have to mean an unsharp lens - if you focused for the center, that is. You may try to focus for the corners, but I found it quite hard to do and failed miserably more than once during my test. When testing for distortion, again, try different focusing distances. Most lenses show a lot more distortion at short distances than they do at infinity. Thomas Bantel * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
