Defective EF 35-80 mm Lens?

shaval · Jun 5, 2012

I sold a Canon EF 35 - 80 mm 4/5.6 III Auto Focus Aspherical Ultracompact Lens on eBay and it was returned to me because the lens was defective. The person who bought the lens says that when he zooms in or out the aperture auto adjusts, which seems to be a malfunction. In manual mode on his Canon 60D, aperture should be manual regardless of zooming or not. He tested it out on his friends 5d Mark II and it did the same thing. I tested the lens with a Canon Rebel film camera and it works fine. The aperture or speed does not auto adjusts while zooming, like he says. Are these lenses compatible with newer digital cameras?

Espike · Jun 5, 2012

Well at 35mm, the max aperture is f/4. At 80mm the max aperture is f/5.6. That is part of the design. If the aperture is wide open at f/4 @35mm and you zoom to 80mm, it will stop itself down to f/5.6.

Dao · Jun 5, 2012

You can tell the buyer that's normal behavior of that particular lens. Or any zoom lenses that have the notation of f/x-y (i.e. f/3.5-4.6 or f/2.8-4) where the max aperture varies with focal length. You can ask the buyer to adjust the aperture to f/8, change the focal length and see

Or have the buyer go to any photography related forum and ask the same question.

shaval · Jun 6, 2012

What I mean here is that the aperture changes while trying to focus.

Dao · Jun 6, 2012

shaval said:
What I mean here is that the aperture changes while trying to focus.

But you said zooming in the original post. Like change the focal length of the lens.

Crollo · Jun 6, 2012

You said 4 times in the original post that it was related to zooming. Now you're saying it's focusing. Wonderful.

shaval · Jun 7, 2012

There's no focal lenght zooming on this lens. The only thing that zooms is the autofocus.

Dao · Jun 7, 2012

If the lens said 35-80mm and cannot be zoom, then it is a defective lens.

Zoom range: 35mm to 80mm

So you should be able to adjust the focal length of the lens from 35mm all the way to 80mm.

TheKenTurner · Jun 7, 2012

shaval said:
There's no focal lenght zooming on this lens. The only thing that zooms is the autofocus.

Then it's a prime lens. Can you post a picture with labels showing what you touch when the aperture changes?

-ken Turner

unpopular · Jun 7, 2012

eyiyi! are you the same person that sold me the 28mm with the oil free and snappy aperture which wouldn't stop down because of its oily and sluggish aperture?

shaval · Jun 8, 2012

You turn the lens barrel to change aperture but it doesn't go zoom zoom cos it's manual not electric. I don't know what the buyer is refering to when he says that he "zooms", I thought he meant the autofocus. The aperture cannot change when the lens focus, right?

TheKenTurner · Jun 8, 2012

shaval said:
You turn the lens barrel to change aperture but it doesn't go zoom zoom cos it's manual not electric. I don't know what the buyer is refering to when he says that he "zooms", I thought he meant the autofocus. The aperture cannot change when the lens focus, right?

Can you speak english? I think I smell a troll...

-ken Turner

Dao · Jun 9, 2012

shaval said:
You turn the lens barrel to change aperture but it doesn't go zoom zoom cos it's manual not electric. I don't know what the buyer is refering to when he says that he "zooms", I thought he meant the autofocus. The aperture cannot change when the lens focus, right?

Zoom usually means change in focal length. Zoom in or Zoom out. It is a term often used in P&S cameras.

According to Canon Lens Museum page, there are quite a few EF 35-80mm lens. But they are all EF 35-80mm f/4-5.6. What that means is at focal length 35mm, the max aperture size or f number is f/4 and the it is 5.6 at 80mm. That is the physical property of the lens.

Let say when a person set the aperture to the widest at 35mm (which is f/4) and he "zoom" or say, change the focal length by turning the focal length ring to 80mm, the person will notice that the camera is now say the aperture is f/5.6 instead of f/4. It is because the max aperture of the lens at focal length 80mm is f/5.6 (smaller is physical size when compare to f/4). And it is normal for a lot of consumer grade zoom lenses. Please note that if the user set the aperture to a small size (larger the f number), the aperture number could stay the same throughout the range of the focal length. For example, at 35mm, the user set the aperture at f/8. When he/she turn the zoom or focal length ring so that the focal length is now 80mm, the aperture will stay at f/8. It is because f/8 is already smaller than f/5.6 (in physical size).

Of course, there are lenses out there that do not change the "MAX" aperture when zoom in and out. And those lens usually cost more. i.e. EF-S 17-55mm f/2.8. As you notice, the notation is f/2.8 while your lens is f/4-5.6. So the max aperture for focal length 17mm is f/2.8 with it is also f/2.8 for 55mm.