6 replies to this topic

[Tony]

A good friend gifted me with this lens recently.  I decided to give it a go yesterday with harsh sunlight and wind gusts.

 

The lens is compatible with my Canon EOS Rebel T5 body.

 

I started out with: 1/60s, F/8, ISO 100 and Manual Exposure Mode with Multi-Segment Metering.

 

One shot and not surprised to see the image was very overexposed, so I stopped down to the maximum F/22, took another 

 

shot and the image was even more overexposed.  I increased shutter speed to 1/125s and still the image was grossly overexposed.

 

I then increased shutter speed to 1/800s and the image was nearly perfectly exposed.  This is my first experience with Third 

 

Party Equipment and my first thought was perhaps my friend was playing a joke on me.

 

I then came indoors and tried using it in our Family Room, no flash mind you and the same situation occurred.

 

 

This never has happened with any of my Canon EF-S lenses.  I wonder how a third party lens would cause such an anomaly as this.

 

Thanks for any and all assistance.  Tony

[Fletch]

No clue as to me it sounds more like a camera issue, maybe the pins need cleaning?

[Merco_61]

The aperture is electronically controlled in a Canon. Sounds like dirty contacts or a burnt-out aperture unit.

 

How old is the lens? Third-party lenses sometimes don't work as expected with bodies that are newer than the lens if the camera manufacturer has changed things in the communications protocol.

[Tony]

The aperture is electronically controlled in a Canon. Sounds like dirty contacts or a burnt-out aperture unit.

 

How old is the lens? Third-party lenses sometimes don't work as expected with bodies that are newer than the lens if the camera manufacturer has changed things in the communications protocol.

Today I cleaned the contacts on both the lens and the camera.  These contacts are different than what we would find on a Nikon or Pentax body.  They are 

 

similar to contacts on SD Cards.  With a flash unit, I started out at 1/60s, F/4.5, ISO 100 indoors.  The image looked very good, surprisingly.  I then took several more shots stopping down the lens several stops and the image became brighter and brighter even at maximum F/stop at F/25.  I then went ahead and 

increased shutter speed along the way and eventually at 1/500s, the image turned out very nice.  Well, logic told me that the only way to get decent 

images with this lens and body combination is with the shutter speed dial.

 

I believe the word, "Compatibility" is subject to whose definition it is.  Admittedly, I do like the lens.  The sharpness and colors rendered are very good in my opinion.  The Auto-Focus is slow and a bit noisy, but overall it does a nice job.  It is a bulky and weighty lens so I use it only when on a tripod.

 

I would like to continue working with it and will report back any further unusual circumstances.

 

Thanks for the helpful hints and suggestions.

 

TT

[Tony]

Moving on with this issue, I will not post many numbers with a lot of detail.  I will post that after a lot of work, patience and tenacity, I believe the key to getting

 

this Sigma lens working properly with the Canon EOS Rebel T5 body, is by using TV (Shutter Priority) mode, both indoors and outdoors.  Just a few minutes 

 

ago I posted an image in Nature and Animals and I believe the subject turned out quite sharp for handheld.  The crank on my tripod is now frozen in position

 

and need to figure out what is going on.  Well, best wishes and thanks so much for viewing.  Peter, I do not know how old the Sigma lens is, although the lens does not have any type of Image Stabilization, but next time I talk to my friend I will be sure to ask him.  

 

TT

[Bengan]

Sounds to me that you have a lens with a "sticky" aperture. Is the shutter mechanic or electronic on this lens?

[Tony]

Sounds to me that you have a lens with a "sticky" aperture. Is the shutter mechanic or electronic on this lens?

Of course you could be exactly right.  I do not have any problems with any of my Canon lenses on the T5.  So hopefully the shutter is working fine.  I do not

 

know what else to do other than working within the confines of this lens and body set up.

 

Thanks for your suggestion. 

 

tt