georg_ditti_

I'm using the 24/1.4 for astrofotography, but I'm not happy with the results. Wide open or stoppes down up to 2.5 it shows severe astigmatism in the edges, despite the smaller chip of my 10D.

 

This lens has only one purpose: It catches the last photon if there is only little light available. That's all. It's to limited for the money

I agree with Yakim. I bought four years ago the 100-400/4.5-5.6 IS, an incredible expensive but real fascinating lens. Since then I made several trips to east asia, two times to southern africa and to the shetland islands with great results.

 

Please keep in mind, that the awful lot of money you spent for such a lens spreads itself over the years. I reckon with 20 years of operation at least ...

 

On the other hand, fund raising takes a lot of time. An alternative ist the 180/3.5 macro from Sigma, a really decent lens. Combine it with the 2x converter, but be aware that with converter its only MF. But there is a little trick to overcome this limitation: Put a small piece of tape over the outermost three contact pads on the left side (look from rear) and mount the extender then: AF will work fine under well lighted conditions.

 

The results you can get with the Sigma EX 180/3.5 macro are stunning.

 

Best wishes, Georg.

I like this lens very much despite beeing a little bit sceptic at the beginning. It delivers stunning sharp images even close up or at low light conditions at full aperture.

 

I made a star test at 70 mm mounting my 10D on my telescop an shot some images of the Pleiades. I've found out, that the infintity mark of my copy is not correct and an inner group of lenses are slight shifted out of the optical axis, but refocussed the results were remarkable sharp for a zoom lens with this large aperture. Please keep in mind, star testing is a real brute test for any optic.

 

best wishes, Georg from Bonn

I am using the 24-70 / 2.8 EX most of cases with my 10D. I didn't expect too much, but I was really amazed by the sharpness, even in the edges. Additional you get satisfying macro function. It's really an allround lens for daily work. Enlargements up to 12 * 8 are not the problem ...

Hi Jorge,

 

Don't misunderstood me. My 24-70 performs satisfying at full aperture as well. No lens, even my incredible expensive 1.4/24mm L shows pinpoint stars.

 

I mean, at f5.6 up to f8 the lens works nearly to perfection.

For normal I'm a sharpness fanatic, using macro lenses for standard and tele images and highly corrected moderate wide angel lenses stopped a little bit down. Only for quick'n'dirty shots I bought the Sigma 24-70/2.8 ...

 

... and was amazed how sharp the images are, particular in the edges. Not at full aperture, but with f5.6 up to f8 it performs very well. This is valid for the 10D ...

 

I tried also astrophotography: The infinity mark of my sample ist not correct, but it is possible to focus the lens to both sides of the infinity mark to find out the optical focus. The stars were no pinpoints, but near by. A slight trace of sperical aberation remained. The lens is sensitive to flares but not too much.

 

Nevertheless: The price/performance is nearly unbeatable, if you stop it a little bit down.