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07-31-2010, 05:07 AM   #1
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How to use the K500mm/4.5

Hi everyone:

I just received my K500/4.5 and just couldn't get it to work

I purchased it from a dealer and he hasn't any idea how the lens operates

Hoping those who have handled it before can share their experience here

I must admit. I don't know even know how to change the aperture setting

Then there's this free rotating ring in between the focusing ring and the tripod mount. What's that for please?

Finally, any tips on how to get the best out of this monster lens please?

My sincere thanks to everyone for their contributions

07-31-2010, 05:23 AM   #2
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I don't own this lens but I'll try to help you; if I remember well there is no automatic control of the diaphragm; you must control the diaphragm not with the body but with the diaph setting on the lens. You will need a very good tripod; it is a manual focus lens, and a precise focus is difficult to achieve; use OM-53 to magnify the viewfinder or use live view
Focus wide open and then close the diaph before shooting
The rotating ring must be a focus selector; you focus the lens, screw the focus ring and then you'll ba able to "recall" the focus manually, turning the focus ring will mark a stop on selected focus.
Notice that the min focus distance is 10 meters; the lens does not have ED elements so it is not an aprochromatic lens, its design was optimised for B&W film, on digital it will reveal some weaknesses including large amount of chromatic aberration
Regards
07-31-2010, 05:33 AM   #3
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Hi,
You should be able to set the white dot on the aperture you want and use the ring to open it for focus and close it to take a picture. The whole rear section comes off if you loosen the knurled ring in the back for use of filters so be sure it is tight. I got some pretty good shots with the one I had, especially with the k100d. I found it hard to use because of the front heaviness and made a long bracket to help.
07-31-2010, 06:38 AM   #4
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Thank you very much, goubejp and borno

I just realised just how bad my technical knowledge on lenses is :ugh:

I don't seem to understand much of what both of you have written here. Really, it's my fault

Hope you don't mind putting them in even simpler language for me

Thank you very much

07-31-2010, 08:27 AM   #5
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Here is a copy of the manual for the K series super telephotos:

http://www.pentax.ca/pdf/o_manuals/om_SMC500MM1000MMREFLEX_e.pdf

Also remember to use a good sturdy tripod.

Phil.
07-31-2010, 08:47 AM   #6
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Thank you very much, gofour3

I'll be putting the manual to good use immediately

Hope to be able to share some good pictures with everyone soon
07-31-2010, 08:50 AM   #7
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QuoteOriginally posted by goubejp Quote
I don't own this lens but I'll try to help you; if I remember well there is no automatic control of the diaphragm; you must control the diaphragm not with the body but with the diaph setting on the lens. You will need a very good tripod; it is a manual focus lens, and a precise focus is difficult to achieve; use OM-53 to magnify the viewfinder or use live view
Focus wide open and then close the diaph before shooting
The rotating ring must be a focus selector; you focus the lens, screw the focus ring and then you'll ba able to "recall" the focus manually, turning the focus ring will mark a stop on selected focus.
Notice that the min focus distance is 10 meters; the lens does not have ED elements so it is not an aprochromatic lens, its design was optimised for B&W film, on digital it will reveal some weaknesses including large amount of chromatic aberration
Regards
I'll try to explain in simpler words :
no automatic control of the diaphragm means that the body cannot close the diaphragm by itself; on all recent lenses if for instance you select f8 on the diaphragm on a f4.5 lens, the lens remains open at f4 to help focusing and the diaphragm is closed just when the shot is made; it is easier to focus at f4.5 because the depth of field (ie the depth of the zone in which image is sharp) is narrower than at f8 and because also the viewfinder is brighter.
ED means extra low dispersion glass; all long telephoto suffer from chromatic aberration; because a glass element does not deviate all light wavelength (colors) by the same amount; these long tele with 100 mm + front element are prone to that. To correct this perfectly you have to introduce special glass element, like ED element or fuorite on Canon lenses (both are extremely expensive). You find now these ED glass on all modern telephotos (EG DA*200, DA*300, FA*600...). With this old lens design this is not corrected; many users apparently reports that images are fairly sharps but you'll observe some purple fringing on the images; this is often reduced by stopping down (at f8 for example)
See an example of purple fringing with a DA*200 wide open :

Corrected when stopped down at f5.6 :

Regards
07-31-2010, 09:20 AM   #8
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Thank you very much, gobejp

Yes, I understand your points now

Now, to put all your advises to good use

07-31-2010, 10:17 AM   #9
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Here are a couple old samples w/ k100d, probably f8 or so:



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