750d + Sigma lens - focus problem? (1 Viewer)

New camera arrived today and test drove it with an old sigma APO lens.

It only works in AP and wide open. The pictures are ok but not too sharp. I also took some pictures of a Griffon (big!) but the pictures are badly out of focus. I will attach later.

Its bizarre because when looking through the viewfinder all the pictures were really sharp but press the button and they're not great. I could clearly see the underside of the bird. I don't understnad whats happening between this and registering the photo. Some of the photos were at 1/1600 and 1/1000 sec so they should be sharp?

I also took so pictures of some static objects bark on trees etc. - all hand held. I tried manual focus - agin clear through the viewfinder but not on review.

I have read about fine tuning the focus.

I'm off to experiment with the normal lens but if anyone has any interim ideas let me know. As said I'll try to put some pictures on later...

If I'm honest its why I stopped using the lens before but I'm hoping now there might be a fix.

Rosbifs

The lens probably needs re-chipping.

Cheers.

Steve.

As Stevo states your lens may need a new chip. Contact Sigma for help.

I turned the camera to M and wacked the speed up to 1/2000 and higher and the results are better with the Sigma. The cannon basic 18-55mm produces great results so its not the camera.

I was doing some rough maths - 500mm sigma x factor 1.6 = 800mm
So I really need to be shooting in the 1/1000's to stop camera shake.

I will contact Sigma at the same time but the lens is 'old' 20years...

i think you will find that Sigma no longer have the chips for old lens

rosbifs said:

I turned the camera to M and wacked the speed up to 1/2000 and higher and the results are better with the Sigma. The cannon basic 18-55mm produces great results so its not the camera.
...
I will contact Sigma at the same time but the lens is 'old' 20years...

Click to expand...

This happened to me when I moved from my Eos 50E (or possibly, the earlier Eos 600) to a current camera (Eos 3 or 10D, can't remember). I was so looking forward to using my Sigma 500 F/7.2 APO but after one "shot" the camera locked and needed resetting by taking the battery out. Sigma UK did re-chip one lens for me, but couldn't help with my "birding" lens. I remember something being said that Canon had changed the voltage necessary to drive the aperture motor.

Malcolm Stewart said:

This happened to me when I moved from my Eos 50E (or possibly, the earlier Eos 600) to a current camera (Eos 3 or 10D, can't remember). I was so looking forward to using my Sigma 500 F/7.2 APO but after one "shot" the camera locked and needed resetting by taking the battery out. Sigma UK did re-chip one lens for me, but couldn't help with my "birding" lens. I remember something being said that Canon had changed the voltage necessary to drive the aperture motor.

Click to expand...

Oddly enough, my old SLR was a 50E and I too used it with a Sigma f/7.2 500mm APO. When digital started taking off I investigated possible options (this was quite a few years ago, can't remember the details) and concluded that trying to get the lens rechipped for a DSLR was unlikely to be worth it. A couple of years ago I did get my first DSLR and long lens, and compared the results with what I used to get with the Sigma. The latter now look pretty unimpressive, though I liked the lens at the time.

Looks like I will be going down option 2 - cheap zoom followed by something else later on....

Mate don't do cheap, you wont like the results
The "new" Tammy 150 - 600 or the Siggy equivalent are nice pieces of glass.
Worth waiting and putting the Franc's away for.
Ebay has good deals on 2nd hand.
Cheap glass is just that