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Problems with smc M 1.7 50mm

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ojan

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Hi Folks!

I've been lurking around this very nice and informative forum for some months now and finally bought myself a k10d with the kit lens a month ago.

The camera hasn't disappointed me but I do have some problems with an old smc M 1.7 50mm lens. I can't produce sharp images with this lens.

I bought it together with a smc M 3.5 135mm lens which is very nice and very sharp.

Please have look at http://picasaweb.google.com/oejvinds.postkasse/Tests?authkey=1QE9xm9zpXY and see if you can draw any conclusions.

The pictures is a series of images starting with f/1.7 1/1000 ISO 100 and ending with f/22 1/60 ISO 800.

If you look at them at 100% you will see that none of them are completely sharp.

It looks like blur but at 1/1000 I find it hard to believe.

The second problem with this lens is that it underexposes with 2 stops!

Hope you got some ideas?

Best regards
ojan
 
Frankly I see nothing wrong with the focus on my monitor perhaps you are having other problems in viewing them, I have the same lens from an old Pentax ME and it is as sharp as a tack. I do have exposure problems with the K10 but when on my DL it is just fine.
--
guy
 
If you do a search back you will see that I have also been experiencing some

soft image issues with the old fast primes. Your images seem to be less problematic than mine, but its at full size that the 'softness' becomes most evident. I found that close ups were less problematic, I could get images almost acceptable, but medium to infinity it was almost impossible to distinguish any focal plane what so ever. The whole image looked unacceptably soft. I know its a narrow DOF at 1.4/1.7, but there ought to be at least a hint of a focus plane in there somewhere.

This is a problem I didnt see with these lenses on the DS2 or that I remember when it was on my old film SpII... which I used open a LOT!

Stopping down definitely improves the images, but the fast advantage goes out the window and its just as easy to leave the 17-70 on. And yep... there are exposure issues as well as you stop down thru the F stops.

Try some landscape pics and post your results. I for one would be very interested in your results. NogBoy
 
ojan said:
The second problem with this lens is that it underexposes with 2
stops!
Click to expand...
what do the blades look like? do they close uniformly? they should be completely oil-free, and snap open & shut very quickly when you move the lever by hand.

you could try another manual 50mm to make sure that it's not an issue with the camera... did you try using the lens in full manual mode only? no green button?

the couple of pics that i looked at are pretty sharp.

--
dan
 
Hi Folks!

Thank you for your time and your interest.
i've just uploaded a new image to make my point clearer.

Have a look at http://picasaweb.google.com/oejvinds.postkasse/Tests/photo?authkey=1QE9xm9zpXY#5067244194276633634

Focus should be on the blue flower but if you look at the left edges of the flower you'll see it kind of doubles - it's like being drunk.

I've read about the underexposure in other threads but there it seemed to be all manual lenses or none - I have one working and one not working - and it occurred to me that it might come down to individual lenses and not the camera.

Best regards
ojan
 
Ojan, Your image doesnt look all that bad but its probably the devil in the detail... which is a little hard to make out with what you have here. My experience is that up close the images seem to improve re sharpness. Which seems a bit weird as the DOP shrinks in that direction. Have you tried some landscape type pics to see what you're getting? Am interested in seeing whether you and I have got similar issues.

I have uploaded some of my images to Flickr so some of you folks can take a gander at what I've been getting. Heres the link:

http://www.flickr.com/photos/8329197@N04/

Got tons more if you want to see. NogBoy
 
Sorry Still can't see anything wrong. If all your pictures come out this good you should be very happy with the results. If you want to predict results take up painting and use an artists brushes
--
guy
 
ojan,

This image is not normal; my M50/1.7 does not do this at least. Perhaps a lens element has come loose and is misaligned?
ojan said:
Hi Folks!

Thank you for your time and your interest.
i've just uploaded a new image to make my point clearer.
Have a look at

http://picasaweb.google.com/oejvinds.postkasse/Tests/photo?authkey=1QE9xm9zpXY#5067244194276633634

Focus should be on the blue flower but if you look at the left
edges of the flower you'll see it kind of doubles - it's like being
drunk.

I've read about the underexposure in other threads but there it
seemed to be all manual lenses or none - I have one working and one
not working - and it occurred to me that it might come down to
individual lenses and not the camera.

Best regards
ojan
Click to expand...
--
[ http://www.flickr.com/photos/agis/ ]
[ http://amagawa.deviantart.com/ ]

 
I use this lens with my K100D and am having some of the same issues. Took it to the beach in the morning and ended up with sunset pictures. I am ready to chuck it and go with the Sigma 17-70.
 
ojan,
I have a M1,7 50mm and got the exact same problem ...

I tried to make some comparaisons with the kit lense at 50mm, and it seems way less sharp than the kit lense. I tested at various F and it is improving over F8, but still ...

My only goal with this lense was to use it in low light (between 1,7 and 4), but the results are so blurry that I am sticking to the kit lense :(
If you get any explaination except bad copy, I would be very happy
 
I have been using the M50 1.7 almost exclusively since I got my DS 2 years ago and I can't see any problems. Images are very sharp, bokeh and colors are fantastic.
--
Add yourself to the map !
http://www.frappr.com/pentax
 
It looks rather like camera shake. It shouldn't be at 1/125s and 50mm and presumably SR on, but I wonder is it because the lens is short and you're holding the camera different?
 
SteveB said:
It looks rather like camera shake. It shouldn't be at 1/125s and
50mm and presumably SR on, but I wonder is it because the lens is
short and you're holding the camera different?
Click to expand...
Good suggestion. He also focused behind the flower.

Was it windy, even slightly? The white parts of the blossom look like they were moving. Partly cloudy days will drive you crazy trying to shoot flowers, The temperature chage as the clouds move across sets up enough of a breeze to really get the flowers moving. You might not have felt it, but the flower did.

Secondly, SR corrects for lateral movement. Unfortunately, it won't also correct for weaving back and forth (like I tend to do). I've boogered up some excellent pics by weaving slightly.

And last, shooting wide open with the 135mm at f/3.5 will give you more lattitude with focus error than shooting the 50 at f/1.7. It doesn't say in the exif info, but the DOF looks awfully narrow. Try it again with the lens stopped down some. It might solve some of the softness problems.

(Oh. Check the diopter setting. If it's wrong, it might be throwing off the focus you are seeing. It affects the viewfinder but not the image capture. It's probably not the problem since the 135mm pics look okay, but it never hurts to check it.)
 
egarrard said:
SteveB said:
It looks rather like camera shake. It shouldn't be at 1/125s and
50mm and presumably SR on, but I wonder is it because the lens is
short and you're holding the camera different?
Click to expand...
Good suggestion. He also focused behind the flower.

Was it windy, even slightly? The white parts of the blossom look
like they were moving. Partly cloudy days will drive you crazy
trying to shoot flowers, The temperature chage as the clouds move
across sets up enough of a breeze to really get the flowers moving.
You might not have felt it, but the flower did.

Secondly, SR corrects for lateral movement. Unfortunately, it won't
also correct for weaving back and forth (like I tend to do). I've
boogered up some excellent pics by weaving slightly.

And last, shooting wide open with the 135mm at f/3.5 will give you
more lattitude with focus error than shooting the 50 at f/1.7. It
doesn't say in the exif info, but the DOF looks awfully narrow. Try
it again with the lens stopped down some. It might solve some of
the softness problems.

(Oh. Check the diopter setting. If it's wrong, it might be throwing
off the focus you are seeing. It affects the viewfinder but not the
image capture. It's probably not the problem since the 135mm pics
look okay, but it never hurts to check it.)
Click to expand...
Hi Folks!

Thanks

You might be right both of you but i think camera shake normally gives you soft pictures not this kind of "doubleness".

I think the photo was taken at f2.8 or f3.5 but I'm not sure.

I've just uploaded a picture which has the kind of sharpness I'm looking for. It's taken with the kit lens at f8. I know this will give me greater DOF but it's taken at a much shorter distance.
But please have a look at the picture and tell me what you think.

Link http://picasaweb.google.com/oejvinds.postkasse/Tests/photo?authkey=1QE9xm9zpXY#5067486357417684018

I will not be able to do any further investigation for the next couple of days - I'll be working when the light is here but I think i can borrow a M 50mm f1.4 to do some comparisons later this week.

Best regards
ojan
 
NogBoy said:
I have uploaded some of my images to Flickr so some of you folks
can take a gander at what I've been getting. Heres the link:

http://www.flickr.com/photos/8329197@N04/
Click to expand...
that crop of the ladder shows bad focus, not a problem with the lens... look how sharp the grass is.

instead of putting up one object by itself to focus on, stack a series of closely-spaced objects up in a line, one behind the other, but slightly offset... then focus on the center object.

you'll be able to see where the camera is focusing.

--
dan
 
ojan said:
Hi Folks!

I've been lurking around this very nice and informative forum for
some months now and finally bought myself a k10d with the kit lens
a month ago.

The camera hasn't disappointed me but I do have some problems with
an old smc M 1.7 50mm lens. I can't produce sharp images with this
lens.
Click to expand...
Hello. How are you focusing? I mean, are you using the image in the view finder, or are you using the focus confirmation used by the camera?

I have disassembled and reassembled (successfully) many Pentax-M 1:1.7 50mm lenses. There really isn't much that can go wrong with that kind of lens... I would suggest using just the image in the screen to focus. Experiment by focusing just slightly before, and behind subject and take note of what the viewfinder image looks like and if the focus confirmation of the camera agrees with the viewfinder image.

My experience with this lens is that it was suprisingly sharp.

--
Regards,

Cybur

Still thinking of one...
 
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