Sigma 500 4.5 problem

A few months ago I posted mentioning the ghosting/focus problems I had with my Sigma 500 F4.5. Couldn't shoot wide open, had to stop it down 1 maybe 1.5 to get a usable image.

Well Sigma asked for the lens and camera to recal the lens. The safe travelling of the gear worried me.

So I had a thought and removed the clear glass drop in filter. The problem worsened! Dived on to the net and bought a sigma ex dg uv drop in which is double coated to reduced light bouncing back to the sensor.

Problem solved! Can now shoot wide open and even looks good with a 1.4x attached! All I can think is the original filter was faulty/not coated?

Just thought I'd mention this in case anyone else has a similar problem!

regards.
Stu.

Thanks for the feedback Stu, makes sense !!!

I got my 500/4.5 a few weeks back, second hand. The UV filter I have is a Marumi UV filter. I did not notice any issue per se, but I could try to get a high end Sigma or Hoya and see if that makes a difference. What do you think ?

Hi there,

Depends if you are having trouble with flare and ghosting. Was REALLY bad on my copy. Just could not use anything below 6.3 as any white areas especially would ghost.

Sigma did say to get the best from this lens drop it down a stop or two. Unfortunately I bought the lens because I wanted to shoot at 4.5! Never mind, lots better now but still saving for a nikon 500!

My original filter was just a glass filter, no coating etc. This really didn't seem to help.

A 'cheap' way to 500mm but you end up paying down the line.

Have fun.
regards.
Stu.

I haven't had any problems so far, but I'll get my hands on the Sigma Filter, just to see. It can't hurt.

Well, 500mm 4.5 in for repair at a local camera shop as on close inspection still a focus problem wide open, seems i jumped the gun. This chap knows some of the engineers at Sigma UK.

Found out why Sigma wanted my camera to go in with the lens. They shoot a test image with the combi and send it to Japan. There, they make a custom chip for the combi and send it back to the UK for a refit! http://www.wildaboutbritain.co.uk/fo...milies/eek.gif

I've mentioned I update camera bodies every three years. With a custom chip inside, would I have to have the lens rechipped every time? Waiting for an answer. Will let you know.

If the answer is yes, think I'm gonna mention to Sigma UK that under the sales of goods act, it is reasonable to expect a lens to last longer than 12 months and fit other bodies. Thereby, this lens was not fit for the purpose it was sold for. We'll see what comes about. Who know's, Sigma might suprise me and get this lens working as it should!

regards.
Stu.