lens tele extenders


Snapper

Link Posted 24/03/2006 - 11:45
Does anybody know if there are any tele extenders for the *ist DL?

When I used to use my old Pentax spotmatic II, I had a set of 3 such extenders, x1, x2, x3, either singly or all coupled together making a x6 extender, also is there any bellows or perhaps any 1, 2 or 3 times dioptre add on lenses for the same camera *ist DL?
Are any of the above still in use?
Best wishes all.

John

MattMatic

Link Posted 24/03/2006 - 14:34
John.
The short answer is yes

There are several teleconvertors available for Pentax K-mount. Look for an autofocus K mount and you can't go far wrong. (I have the Pentax 1.7xAF convertor which also allows autofocus when using older manual focus lenses. The quality is pretty good indeed.) There are third party models from Kenko, Sigma and the like.

Extension tubes are also available. The third party ones are probably best (since the original Pentax ones didn't couple the electrical contacts). I picked up a set of three second hand from Jessops for about 20.

Again, close up filters are available - they just fit on the front of the lens so you'll need to know the filter thread size. Extension tubes tend to give better results, but close up filters are often more convenient and allow autofocus.

Hope that helps!
Matt

Snapper

Link Posted 24/03/2006 - 18:07
MattMatic wrote:
John.
The short answer is yes

There are several teleconvertors available for Pentax K-mount. Look for an autofocus K mount and you can't go far wrong. (I have the Pentax 1.7xAF convertor which also allows autofocus when using older manual focus lenses. The quality is pretty good indeed.) There are third party models from Kenko, Sigma and the like.

Extension tubes are also available. The third party ones are probably best (since the original Pentax ones didn't couple the electrical contacts). I picked up a set of three second hand from Jessops for about 20.

Again, close up filters are available - they just fit on the front of the lens so you'll need to know the filter thread size. Extension tubes tend to give better results, but close up filters are often more convenient and allow autofocus.

Hope that helps!
Matt

---------------------
Thank you Matt

Coming back after a lengthy break away from photography, I am somewhat at a loss as to the development, although I was thinking along the lines of the extenders as a means of extending my SMCP-DA 50-200 f4 - 5.6 lens and making it more a 400mm lens even though I know that measurement will not be really true since I'm still thinking as with a film camera...So I take it then that the *ist DL is a K-mount, but since I will not be using that magnification often, it does seem a more realistic purchase as opposed to buying a true 400mm lens...

Thread size a 52mm, so consistancy with both my lenses with regards to close-up filters I'm pleased to say.

Thanks again Matt

John

Don

Link Posted 24/03/2006 - 18:40
sometimes it pays to rent or borrow.
If it's a rarely used focal length, and you need max quality.
Fired many shots. Didn't kill anything.

Snapper

Link Posted 24/03/2006 - 18:53
Don wrote:
sometimes it pays to rent or borrow.
If it's a rarely used focal length, and you need max quality.

A logical train of thought that Don and I do agree, but personally I think that if I did rent or borrow, shortly after returning same...I would be wishing I had not as I'm sure I would find another reason to use it at some time in the not too distant future since rent would be more the likely as apposed to find someone to borrow from..

Cheers

John

Kimbo

Link Posted 24/03/2006 - 19:43
Snapper wrote:
So I take it then that the *ist DL is a K-mount

Yes, any K-mount lens will fit but the available auto functions will vary.

KA series lenses are best for manual focus, F and FA series for autofocus.

You're obviously aware that the DA lenses are autofocus but optimised for DSLRs and so you have a very wide choice of available optics.
I see no reason why a regular KA mount teleconverter shouldn't be just as useful with a DA lens as with a traditional 35mm film lens.......unless there's an issue with aperture couplings, but I wouldn't know as I don't have any DA lenses

I can certainly recommend the Pentax AF 1.7x converter though, it's excellent!
Die my dear doctor, that's the last thing I shall do!

Don

Link Posted 24/03/2006 - 19:52
given the 1.5 factor of the digital body combined with an af 1.7 teleconverter, a 400mm telphoto becomes a telescope.
javascript:emoticon('')
Fired many shots. Didn't kill anything.

MattMatic

Link Posted 24/03/2006 - 20:23
Quote:
unless there's an issue with aperture couplings, but I wouldn't know as I don't have any DA lenses

Certainly no issues with the Pentax 1.7xAF adapter. The DA lenses have regular couplings - they just don't have the recessed "finger" that moves with the aperture ring telling the body where the ring is. In all other respects the mount is the same.
Matt

Snapper

Link Posted 25/03/2006 - 07:47
Don wrote:
given the 1.5 factor of the digital body combined with an af 1.7 teleconverter, a 400mm telphoto becomes a telescope.
javascript:emoticon('')

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Don.

I can well imanage the 400mm lens becoming a telescope...hmmm!, food for thought there. ...but I somehow think your slightly off track since I was refering to (in the first instance) of adding my existing 50 - 200mm telephoto to a AF 1.7x...not of a 400mm plus teleconverter.

Thanks for the thoughts though.

John

niblue

Link Posted 25/03/2006 - 18:59
I'd be surprised if AF worked at the long end with the 50-200 and the 1.7x

Snapper

Link Posted 25/03/2006 - 19:10
niblue wrote:
I'd be surprised if AF worked at the long end with the 50-200 and the 1.7x

------------------

Thanks for your imput, I was only making enquiries so no panic..

John

Don

Link Posted 25/03/2006 - 19:40
while the af is sluggish my af 1.7 telecoverter and 70-200 takumar-a 1:4 is usable and I think most would be satisfied.
Fired many shots. Didn't kill anything.

Kimbo

Link Posted 25/03/2006 - 19:55
As with most things AF, the performance of the converter depends more on subject brightness/contrast than anything else.
The AF 1.7x converter is primarily designed for use with fast prime lenses but can still be quite effective with slower zooms.
Even in low-light situations, you can switch the camera to MF and simply focus the lens the old-fashioned way and still benefit from the multiplication factor (use AF to focus on a distant light source to ascertain infinity and then switch to manual).

I must say that the converter was designed for the SF range of 35mm cameras but performs even better on later bodies due to their improved AF systems
Die my dear doctor, that's the last thing I shall do!

niblue

Link Posted 26/03/2006 - 09:38
Don wrote:
while the af is sluggish my af 1.7 telecoverter and 70-200 takumar-a 1:4 is usable and I think most would be satisfied.

Mine used to work fine with anything under F5.6 maximum aperture but didn't always work with F5.6 and above, even with a brightly lit, high contrast subject. The worst offended was the FA 100-300 as with the 1.7x that would never AF near the long end under any conditions.

Kimbo

Link Posted 26/03/2006 - 13:05
Zooms do tend to be less sharp toward the extremes and then there's the inevitable camera shake to deal with too.
I have to admit that it's a bit hit and miss with my 500mm f8 mirror but not a problem at all with my 75-250mm f3.8/4.5.

My favourite tele lens, for use with the AF converter is a 135mm f2.5. At 230mm for film and 345mm for digital, it's more than long enough for most tele uses and still provides a nice bright viewfinder image.
Die my dear doctor, that's the last thing I shall do!
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