Following on from the above, I've just compared the field of view at the short end, which should be 35mm, with that from a DA 35mm AL F2.4, on the same camera, on a tripod, without moving the camera between shots.

The short end of the 35-105 is noticeably longer than the 35mm prime, ie the magnification is significantly greater.

This is consistent with the zoom ring not moving all the way to the 35mm end of the scale, as shown in my earlier picture of the lens.

So I'm increasingly suspicious that there's something wrong with the lens.

Still grateful for any comments about whether this sort of thing is normal. I've never seen the focus scale issue on any lens before, however, so I'm highly suspicious.

Hello all, long time no see! Merry Christmas to all - impressed to see so many familiar names are still about. I haven't done much with my cameras for a long time, but I'd be grateful for a little advice.

A friend has bought a SMC-A 35-105mm F3.5 for her son, who has a K1000 and is getting into all-manual B&W photography.

I'm checking the lens over for her on my K-3 before she gives it to him, and I've found something rather odd about it.

Cosmetically it's excellent, verging on mint. The front and rear elements could do with a clean, but they're undamaged. The aperture control is smooth and the iris opens and closes perfectly.

The focus and zoom rings are tight and smooth, just as you'd expect for a good example of one of the old A series lenses. Exposure isn't bad, indicating that the lens is stopping down correctly.

However.... I've noticed two oddities - one minor, one potentially major.

The minor one is that the zoom ring doesn't go all the way to the 35mm marking at the wide end, as you can see here.

The major one is that at all distances, the focus distance scale is miles wrong. For instance, at the 105mm end of the zoom I can focus on chimneys half a mile away, and the focus scale says 3m (yes, three meters). At the 35mm end, the effect is even more pronounced - I have to shift into macro mode to get the same chimneys sharp with an indicated focus distance of under 1.5 m.

I've got the K-3's AF set to use the center spot only, and the visible sharpness in the viewfinder corresponds to the in-focus hexagon. I've also tried the lens on my K5-IIs and the issue is exactly the same.

I can't believe this can be right - it seems like there's something very wrong with the internals, but I'd be grateful for any thoughts or comments.

I've cross posted this at PentaxForums - hope that's ok but as my friend has only a very short time to decide whether to give the lens to her son or return it to the eBay seller, I was hoping for as wide an audience as possible. Thanks in advance.

I don't really post here any more, but I happened past, and noticed this thread.

For the record, SRS have provided me, and latterly my dad, with some absolutely excellent service over some trade-in deals.

The K-3 and 18-135 I have now are very much down to the trade in value I got from SRS for a whole bunch of old stuff, and the K-5 II that my dad has, is similarly down to his being able to trade in a lot of old lenses and an old body with them. There was one old item that they weren't interested in, but quite a few others that they were, that I wasn't expecting to fetch anything at all.

I felt the values placed on the old gear were very fair indeed, and the whole process was perfect from end to end. I suppose I might (or might not) have got a few more quid if I'd sold the bits individually, but the complete lack of hassle was worth a great deal.

I have no connection with SRS other than as a very satisfied customer (including once, when I had an expensive lens go wrong within warranty and I got to see how well they sort things out, as well as do the selling in the first place).

I expect there are other good retailers, but I've dealt with SRS for a long time now, and they've been so consistently good that I wouldn't consider buying expensive gear from anywhere else these days unless they actually didn't stock it.

Yes, very much agree.

No, I was wrong to say that the exposure doesn't change. Algi was right to point that out. Albeit in his own inimitable style

Yes, sorry. Of course the exposure changes - if you magnify the same subject area over more pixels on the sensor, the light coming off the subject is spread over more pixels, so the exposure per pixel is less.

Sorry for the confusion, posted too quickly there.

However, the tubes don't affect the focal length of the lens. How can they? You might just as well say that the lens has a different focal length in your hand than on the camera.

Magnification, of course, is another matter. Of course tubes increase the magnification.

But the additional magnification comes from the subject being closer, not because the lens is suddenly a different focal length.

Extension tubes are not lenses. They have no glass in them.

Therefore they do not change the magnification you get from the lens you use. Consequently they don't change the exposure either.

The only thing they do is allow whatever lens you're using to focus closer than it can without the tubes.

Closer subject = bigger image.

That's all.

The thing about that one, apparently, is that AF lenses will still AF with it, as well as letting the auto-exposure information pass through as well.

4?

I can only find three

Ooo, ooo, ooo....

Here's what you want.

Forget the TC, but it's the right tubes. You'll just have to scratch a bit of paint off.

Blimey, or these, without the TC...

... you wait for hours, and then two come along at once.

I don't see any reason to avoid using a zoom with tubes. The tubes just move the lens away from the body, thus allowing the point of closest focus to be closer than without the tubes.

Closer subject = bigger image, that's all.