20 Most Recent Sigma 28-300mm f/3.5-6.3 DG Lens - Page 3 Questions & Answers

If it is a dynax compatable lens it should work The really old 75-300 shiny black finish will not work
and can not be rechiped

Sigma makes their lenses with a variety of mounts. If the lens has a Pentax mount then it will work with your K20d.

some of the older sigma 70 -500 lenses had a little rubber belt driving the focussing. you can access this by removing the mount ring, four screws and two on recessed on the side holding the contact also three screws holding the centre black cover. the belt used to stretch therefore no longer driving the focussing ring.

My guess is the camera tries to go to a high ISO. Easy to check in NXview. Switch of the OS, put the camera on a tripod and use a low iso, to see if you can make pictures without grain (digital noise) I know that is not an option for you in the field, but just to see the lens and your camera can make beautiful pictures. Newer camera's can work with higher ISO, without seeing digital noise. Buy a second hand (new in the Xmas sales) D7000. You can easy shoot till ISO 3200 and hardly see any noise.

Do you have a question about this lens?

What make and model camera? Which Sigma lens? Do you have autofocus turned on, both on the camera and the lens?

What is the make and model

If you're referring to the numbers on the aperture ring, you don't use them. Simply turn the ring to its smallest aperture (largest number) and leave it there. Just use the lens the same way you use any other lens without such a ring.The aperture ring is there for use with older cameras that don't control the aperture from the camera.

Haze can be from the lens or the camera sensor in some extreme conditions.

You didn't say the camera model - but I'll assume a modern, DSLR type with removable lenses. First, try a different lens. If the resulting picture is clear, the problem is with the lens. If the problem still exists, then the problem is with the camera. You may have some luck cleaning the sensor of the camera. This is a *very* delicate procedure and is done with some very specific tools and supplies for the job. The wrong procedure or use of improper cleaning supplies can render your camera useless.

The same holds true for the lens. These are delicate, precision optics and should not be serviced by end users. You should inspect the lens by holding the aperture fully open and look through it front to back and back to front. Gently clean the front and rear glass with lens cleaner and leans cleaning tissues. Do not rub hard. The coating on "Single Coated" and "Multi-Coated" optics can be damaged if rubbing too hard.

If the source of the haze is still present (either in pictures or with the ***** eye looking through the lens, it should be returned to the factory or authorized repairer for a repair estimate.

i hope this helps & good luck!

Hi, I strongly doubt you would be able to fix it yourself. My suggestion would be to contact Gus Lazzari he seems to have access to a lot of camera and lens parts no matter how old they are.

your best bet is to go to the manufactures website. Here is the manuals for all of the cameras they make. Find yours and download


http://www.sigma-photo.co.jp/english/support/catalogue/use.htm

You should send it to Sigma for repair.

Their contact information is right here:

http://www.sigmaphoto.com/contactus

The conversion is not realistically possible, sorry. The SA mount is physically the same as a Pentax K mount but even then has a different flange distance, so even conversion to Pentax would be difficult. The electronics will all be custom made to suit Sigma SA standards.

Even if you had the machine shop skills and technical wizardry needed to convert to a Nikon AF mount, it's unlikely that the lenses would ever be fully compatible and they would be unlikely to work on subsequent Nikon bodies.

It will be cheaper and far more practical to sell what you have "as is" and use the funds towards the purchase of good used Nikon branded lenses.

unfortunately sigma lenses do have problem with sony a55. I need to be returned to dealer to be re-chiped

No. Nikon has been using the same lens mount since about 1959. Pentax has changed their mount once since then, but not to the same thing.

Here is an answer from Questionhub.com:
The D40 and D80 can both communicate with lenses electronically, but in addition to this only the D80 has a mechanical coupling - sort of a mini screwdriver in the lens mount.
So the D40 can *tell* a lens it should focus but the lens has to use it's own motor to actually do this. The only Nikon lenses that are capable of this are AF-S and AF-I lenses (about 30 different lenses in all).
On the other hand, the D80 can *make* a lens focus. If the lens doesn't have a motor, the D80 will use its own motor to pull focus by twirling the mini screwdriver.
The D40, D40X and D60 don't have this feature and the D80 and up do. rek('_tx8');
They say the lenses will autofocus on the D80 and about, but not the D40 or D60.
Good luck, and hope this helps.

George, First check the settings on the front of the camera and the lens if it has them, they have to be set on auto, not manual, The Nikon lenses have a button, the camera has a button, next to the lens release button. It should be AF or a just A. for auto focus. Now,, your sigma might not have all the stuff that the Nikon lens' have, some have a little blade sticking out that turns the focus ring, some are electronic, some have the motor inside like you said. Now I'm not sure about yours, but it should work, did you try another lens to see if it was the camera? If it is the lens, I would take it back, or learn to focus manually. Some of those lens' are manual focus only. Hope this helps.

You are not doing anything wrong. Return this faulty product. J.

The XTi does not have a "full-frame" sensor, so vignetting should not be a problem with this lens.

The only solution is to locate a repair shop and have them determine if there is anything that can be repaired. You don't say what manufacturer the lens is from so I cannot direct you to a shop or manufacturerer's site for repair information.

If the lens is not an expensive model, you may be better off replacing instead of repairing it. These lenses are complicated, rather delicate pieces of gear. There are many plastic parts inside and they really do not respond will to being dropped.

Sorry . . .