smc 50mm

Thanks guys-I've been doing alittle experiment before I read your comments above-I'll try to grips with what you are telling me later.
meanwhile I took some photos to compare aperture settings which I've posted on flickr-at f1.7 and f8-and I can't see any difference between them. I would realy appreciate some feedback-remember I'm a novice and need laymans terms if possible. The photos are of a glass thingy hanging at my window, and it was snowing outside at the time.
here's the flickr link:
http://www.flickr.com/photos/16934477@N03/sets/72157622996000593/

Thanks

I'm wondering if any of those really are at f8?

With an "A" lens like you have, you should have the aperture ring set to "A" and select the aperture via the camera.

Pam, You need to give this lens a better chance to show what it can do. I think you have perhaps picked one of the worst scenarios to test this lens as is possible.

Glass is always difficult, glass in front of glass is doubly difficult, backlit glass in front of backlit glass gives it almost no chance at all.

There is a difference, albeit very subtle, between your f1.7 and 48 images.

Look at the frame at the right hand side. In the f8 version it isn't sharp, but it is slightly better defined than in the f1.7 version.

Are you shooting RAW or JPG?
If JPG, have you got any in camera sharpening selected? If not, what software have you used to sharpen the image?

If none, that's why your images look soft.

Rather than combined shots, can you post individual images of f1.7 and f8 so we can check the Exif info?

Can you tell us the exact wording around the lens's front bezel?

Does it say SMC Pentax, SMC Pentax-M, or SMC Pentax-A, or something different?

If it shows SMC Pentax-A, as iceblinker states, you should use the lens on the 'A' setting on the aperture ring otherwise it's behaving like a SMC Pentax/SMC Pentax-M lens and will only work correctly with the exposure mode dial set to M(anual). If it is an A series lens and you are using the aperture ring and any other exposure mode setting, all images will be captured at f1.7. This might explain why there is very little difference between your shots.

If you post any images here, leave the EXIF data intact so we can interrogate it. No EXIF data exists for the image I viewed on your Flickr page.

Ok it's a pentax smc A lens.
I followed the instructions for setting the lens that I found here;
http://forums.dpreview.com/forums/read.asp?forum=1036&message=24921509
so now I use it a bit like an automatic focus, ie the shutter is locked until it's in focus. I'll need to retry it on a tripod to eliminate any camera shake-but there shouldn't be cause I have stabilization turned on.
I'm shooting jpeg and I didn't process those images at all.

I can't seem to get exif data when using this lens

I'm not sure what you mean here:
If it is an A series lens and you are using the aperture ring and any other exposure mode setting, all images will be captured at f1.7. This might explain why there is very little difference between your shots.

I'm using aperture priority setting.

Thanks again for your help.

BTW I did some experiments not at the window and I wasn't getting much difference there either.

It is possible to use that lens by selecting apertures with the ring on the lens, but then Manual mode on the camera must be used for all but f1.7.

It's easier just to set it to "A". Then the lens will behave just like a more modern one except for the lack of autofocus.

All shots will actually be at f1.7 with Aperture Priority unless you set the lens to "A".

You can ignore all the info about exposure there because that info is for fully manual lenses. Your lens is just manual-focus, but auto-exposure (when set to "A").

I'm more confused than ever now. How do I set the lens to A?

On the Aperture ring you will see the letter A.
Turn the ring so that the A comes towards the white mark on the main lens body. Press the button (to the right of the A as you view the lens from the front)and turn the Aperture ring until the A is in line with the white mark. You can now use the camera to set the aperture.

I think between us, we've identified the problem. Follow davex's instructions, set the lens to 'A' (Auto aperture) and set the required aperture on your camera instead of the lens. Set the mode dial (left side of the top plate) to Av, now you can enjoy sharp images.

Sorted.

Found it!! I'll have a little play around later-thanks you so much guys!!!!

Just wanted to thank you guys again- Davex-you nailed it. Now I can get that variation in DOF that I've been after. Great service!!

Thanks for the tips guys, I've now got two options. The 1.4 that I want, and the 1.7 that I need.
I'll let you know the outcome.
Regards

As I said, if you see a 1.7 for sensible money then just go for it. Judging by prices here it'll be worth at least what you paid if you later decide to buy a 1.4 and sell the 1.7 to help fund it.

That said, you're not likely to want to part with the 1.7. Great little lens!