Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old Dec 3, 2006, 1:40 PM   #1
Junior Member
 
Join Date: Nov 2006
Posts: 3
Default

I'm new to the forum. I used a Pentax ME Super with 28mm, 50mm and 70-210mm zoom many years ago and wore it out. Since then, I've used AF/AE point & shoot (Lazy man's tool) cameras.

I just got a K 100D body to use with the older M Series lenses that I kept after all these years. I've always wondered when Pentax would make a DSLR that could use the older lenses. I wasn't keeping up with DSLR technology and my wonderment has been answered.

I'm using the shake reduction setting in manual mode and I have to set the focal length each time I turn it on.

Should I choose 77 (50mm x 1.5) as the FL since I'm using an old 50mm (35mm) lense or just 50mm?

Since 50mm is considered normal (1X) in the 35mm format is 33mm normal for the DSLR format? Therefore 132mm (33mm x 4) would be4 times magnification in the DSLRformat?
micrometer is offline   Reply With Quote
Sponsored Links
Old Dec 3, 2006, 1:51 PM   #2
Senior Member
 
danielchtong's Avatar
 
Join Date: Dec 2005
Posts: 2,888
Default

micrometer wrote:
Quote:
Should I choose 77 (50mm x 1.5) as the FL since I'm using an old 50mm (35mm) lense or just 50mm?

When it comes to shake reduction, 50mm is 50mm FL. Your FoV may be changed because of crop factor. Not the focal length.

Daniel

danielchtong is offline   Reply With Quote
Old Dec 3, 2006, 2:44 PM   #3
Guest
 
Posts: n/a
Default

and welcome to the forum.
our stories are almost identical. i too had smc-M28,50,10,200 and they are as good now as they always were. i picked up a 70-210 soon after getting the DS. it's a remarkable lens , especially for under $40.. they are however a tad more than that now..

roy
  Reply With Quote
Old Dec 3, 2006, 9:18 PM   #4
Senior Member
 
mtngal's Avatar
 
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,052
Default

Welcome! I'm another one who still uses their old manual lenses, mine about the same except that I have the 24mm 2.8, and my 70-210 died. Not convinced that the DA 50-200 is as good as my old one was (it died before I got the digital camera).

I use whatever the lens says - and that seems to work quite well (I now have a 300mm lens and it sure makes a difference!).
mtngal is offline   Reply With Quote
Old Dec 3, 2006, 10:53 PM   #5
Member
 
Join Date: Nov 2006
Posts: 90
Default

Can I ask a related question....

How do you setup the camera when using a fully manual zoom lens, and you know you're going to be changing focal lengths between shots?

I ask because I shoot a lot of trains, and sometimes I'll take a series of shots as the train gets closer, backing the lens off as the train comes towards me. When I do this, there frequently isn't time between shots to do anything more than refocus as needed.

Then again, perhaps this is an example of a bad time to use SR with a fully manual lens...

Paul
pbender is offline   Reply With Quote
Old Dec 3, 2006, 11:16 PM   #6
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Quote:
Then again, perhaps this is an example of a bad time to use SR with a fully manual lens...
I'd be curious. If it were me, I'd experiment with it and see what happens if you leave the camera set to a focal length somewhere "in the middle" of the zoom range. You may find that it's "close enough" to give good results (or you may find the opposite). lol

Interestingly, everyone assumed that Konica Minolta's Anti-Shake would not work with old manual focus lenses via an adapter, since the camera would not be aware of things like focal length and focus distance (and KM didn't include any kind of mechanism in the menus for setting a focal length, since manual focus lenses via an adapter were not officially supported).

But, someone tested them with and without Anti-shake turned on, and found that the Anti-Shake was still working, despite the camera's lack of knowledge about the lens being used. I doubt it was working as well as it would knowing the lens info, but I saw some images showing it's effectiveness (blur without, no blur with) in a series of images from several Manual Focus lenses a while back. It wasn't that scientific (not like the infamous "lawn mower" test - lol). But, the images convinced me (and the person doing the tests was a reputable guy).

So, they must have used some kind of default parameter in the algorithms to decide how much CCD movement was needed with no lens information visible.

Of course, the Pentax system is different. But, I'd imagine that the algorithms for determining the amount of CCD movement are going to be somewhat similar. So, I'd try it set to a focal length somewhere "in the middle" when using a zoom and see what happens. It may still offer some improvement.

You may want to try it more than one way (I'd imagine that it would assume less movement is needed at a wider focal length, and if you set it too long, it could move it too much).

JimC is offline   Reply With Quote
Old Dec 3, 2006, 11:48 PM   #7
Member
 
Join Date: Nov 2006
Posts: 90
Default

JimC wrote:
Quote:
Quote:
Then again, perhaps this is an example of a bad time to use SR with a fully manual lens...
I'd be curious. If it were me, I'd experiment with it and see what happens if you leave the camera set to a focal length somewhere "in the middle" of the zoom range. You may find that it's "close enough" to give good results (or you may find the opposite). lol
You may be right, but since it will be a few weeks still before I'll be able to test this myself, I thought I would ask to see if anybody had tried it.



Quote:
Of course, the Pentax system is different. But, I'd imagine that the algorithms for determining the amount of CCD movement are going to be somewhat similar. So, I'd try it set to a focal length somewhere "in the middle" when using a zoom and see what happens. It may still offer some improvement.
That's a good place to start in any event.

I may also try the first shot with SR on, and successive shots with SR off. Since it's an external switch on the body, that might be possible without too much contortion.

Thanks,

Paul
pbender is offline   Reply With Quote
Old Dec 4, 2006, 8:05 AM   #8
Senior Member
 
mtngal's Avatar
 
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,052
Default

Never thought about zoom lenses - the manual lenses I use are all primes. However, I have sometimes taken pictures with the wrong setting, and not thought it made that much difference.

For your example, I'm not sure that I'd worry too much about it - if you are taking pictures of trains, I would guess you'd be using a pretty fast shutter speed to avoid motion blur. The camera shake is most noticeable at slow shutter speeds. I'd try two things when experimenting - use a figure that is the middle of the zoom and then try using the longest the lens is capable. See what the differences are, and let us know what you find out.
mtngal is offline   Reply With Quote
Old Dec 4, 2006, 8:56 PM   #9
Senior Member
 
NonEntity1's Avatar
 
Join Date: Jul 2006
Location: Lake Placid Florida USA
Posts: 2,689
Default

IIRC, the manual says to use the longest focal length of the zoom.

Tim
NonEntity1 is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 7:18 PM.