I am about to sell my Sigma EX 50-500, 105 macro and 2x teleconverter to get some cash towards a new Canon L lens. My question is whats going to be my best choice?
I am debating between two but will consider others if suggested (in the same price area).
The Canon EF 100-400mm F4.5-5.6 L IS USM SLR lens or Canon EF 300mm F4.0L IS USM SLR lens. I would guess that 300mm would probably be the minimum I should get for birding. I guess my question would be about sharpness. Is the fixed 300mm going to give noticeably sharper results or would I be just as happy with the 100-400? The apreture difference does not bother quite as much as losing 100 mm but I would give that up for noticeable extra sharpness.
Input needed.
If you are using a 10D I think you might be best to have you camera body checked for focus accuracy before taking the step of changing your lens, many 10D's have had slight problems with focus accuracy when using long lenses, I know of 5 people who have had their cameras recallibrated, this has solved the softness issue! Have you done a few test shots with the 50-500 to check this? if you set up some matchboxes or similar in a row, stepping them back at an angle and photograph them with the camera fixed off to a tripod yoh may well find that the box(es) forward or rearward of the focused one are the sharper, this will give you a measure of how far out the focus is, It is worth noting that as the depth of field with long lenses is much shallower they will show up focus inaccuracies more readily.
Out of the lenses you list here the 100-400mm is the best option, I have had one since they where first launched and it is one of the best, sharpest, lenses I have ever owned, however you will lose A/F with it when using converters. The 300mm f4 IS is also an extremely sharp lens, but it does lack the 'reach' that is needed for bird photography.
Quite honestly though the EX 50-500mm Sigma is a good lens I know a few people here who use them and get very sharp results.
I had a slight focus accuracy problem with my 1Ds when I first got it, Canon recallibrated the body, I took the lens to them also, and it is now pretty well consistanly spot-on.
Nigel,
This is interesting - I have a new 300d and have been strugging with the focus. Do you happen to know if the 300d has this problem? I will try your matchbox test! Do you know how long it takes to get a body recalibrated?
Thanks
Richard