HD Pentax-DA AF Rear Converter 1.4x AW
Yeah, that sounds like me
I'm pretty certain I saw it !!!
This really has gone off topic now
So to recap - I have one of these for sale - £250 inc postage, no offers.
Enjoy your converters chaps, I'm currently waiting for better weather to go wide(ish) with LennyBloke's 645 35mm
If you'd like to see how it went, here's a link to my blog on ePHOTOzine:
http://www.ephotozine.com/user/johnriley1uk-22471/blog/pentax-1-4x-af-converter-...
I've briefly tested it on the 55-300mm and that's fine as well.
John
Does "that's fine as well" mean that
- the 55-300 lens & TC combo autofocuses?
&/or
- the general image quality of the combo is acceptable/good/excellent?
The questions are asked because the 55-300 will autofocus with many TCs, but the image quality is poor with some of them (my 55-300 "does not like" my KENKO 1.4X Pz TC at all!)
Thanks in advance.
John
It also reports the correct actual aperture, so the lens set on f/5.8 reports f/8, which is as close as it can be.
All in all it seems well thought out.
Refards
daronl
The EXIF is interesting. It reports the main lens without mention of the converter, not surprising perhaps as it could become a very long description. It reports the correct focal length, so the lens set on 300mm reports a focal length of 420mm.
It also reports the correct actual aperture, so the lens set on f/5.8 reports f/8, which is as close as it can be.
All in all it seems well thought out.
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
I'm puzzled by your comment John, about the aperture exif showing the ' correct' aperture ... Does a converter have any effect on the lens aperture? I thought f5.6 remained f5.6 even with a converter? I appreciate that there is a light loss of a stop our so ... But that would only increase the shutter time value to compensate ... You seemed to be saying that with the converter f5.6 became f8 ....
Quick explanation:- F stop is the ratio of focal length to aperture diameter. The aperture diameter stays the same wide open, but the focal length is increased, hence the F stop (ratio) decreases. The camera doesn't try to adjust exposure, just reports the "true" f -no.
https://www.flickr.com/photos/arleimages/
Now add a 2x converter so 100mm focal length and therefore 100/25 = 4 and it's now an f/4 lens.
1.4x converter = 1 stop difference
2x converter = 2 stops difference
The exposure does change accordingly, but the beauty of it all is that the focusing distance remains the same, the magnification has increased. Great for close up work.
For those with DA*300mm and a K-3, how does the image quality with DA*300mm on the HD Pentax-DA AF Rear Converter 1.4x AW on compare to just cropping to the same field of view on just the DA*300mm on its own?
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1753 posts
16 years
Plymouth,
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Plymouth Photographer