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$199 focal reducer speed booster adapter Pentax PK K to Sony NEX
Posted By: jogiba, 05-08-2013, 05:10 PM

QuoteQuote:
Focal reducer/Speed booster adapter

for/Pentax PK K bayonet lens to Sony NEX mount 5 6 7 camera FS700 FS100

All metal structure, with excellent opticals (4 elements/2 groups, super multi-coated)
what it does:


reduce the focal length (by 0.72x wider)


Ex. 50mm lens on NEX with the adpater, eff. focal length is 50mm x 1.5(crop) x 0.72 = 54mm

 

effectively increases the maximum aperture of the lens by 1 stop




(in other words, under the same aperture, you can use faster shutter speed (by 1 stop).

  what it does not:
there is no electronic integration, no auto fucusing

(you still need to manually focus your lens and aperture, etc.)
Focal Reducer Speed Booster Adapter Pentax PK K to Sony NEX 3 5 6 7 FS700 FS100 | eBay




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05-13-2013, 11:07 AM   #16
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vodanh, I should have prefaced my post. What I was getting at is that this adapter (actually the optic group only) might fit inside the huge space in the K-01 with a lil bit of room so it would mount (totally recessed) just like any flanged adapter. Then you'd be able to get the benefit(s) of the turbo "equalizer" with the K-01.

05-13-2013, 11:12 AM   #17
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Wouldn't it still mess up registration distance?
05-13-2013, 11:43 AM   #18
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QuoteOriginally posted by VoiceOfReason Quote
Wouldn't it still mess up registration distance?
Depends on the optical design. If the "lens turbo" telecompressor has the same K-mount to E-mount distance as a non-optical adapter, then it wouldn't make a difference. The light is just getting "concentrated" into a smaller image circle at the same image plane. If it's optically designed to focus the adapted lens at a different plane (but not sure why that would be done - that's just added complexity), then it could be less or more.

Unlike a teleconverter, these are not optically enlarging the image circle, but compressing it. Much easier to do within the original flange distance, I think... where's that optical designer when you need him/her? (I keep thinking of how the image gets larger when you move a projector away from a screen, etc.)
05-13-2013, 12:44 PM   #19
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This adapter reduces the registration distance of the lenses, so the Pentax lens would have to be recessed into the body.

05-13-2013, 12:52 PM   #20
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QuoteOriginally posted by kenafein Quote
Not that you need it, but are you buying one? I'd be interested in a quality analysis.
I could use my fast lenses like 24mm F1.4 Rokinon PK mount lens with it in APS-C mode on my NEX-VG900 but I don't think it would have that much advantage over full frame mode. It would be great on a NEX-6 or other APS-C NEX camera but until I get an APS-C NEX I will stick with using my full frame lenses in native FF mode.
05-13-2013, 01:15 PM   #21
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QuoteOriginally posted by jogiba Quote
I could use my fast lenses like 24mm F1.4 Rokinon PK mount lens with it in APS-C mode on my NEX-VG900 but I don't think it would have that much advantage over full frame mode. It would be great on a NEX-6 or other APS-C NEX camera but until I get an APS-C NEX I will stick with using my full frame lenses in native FF mode.
Wasn't sure if you had an APS-C, for compact use, or not. I am really looking forward to the FD version. With that, and an FD -> M42 adater, I'll be pretty happy. Here's hoping the quality is up there with the Metabones.
05-14-2013, 08:32 AM - 2 Likes   #22
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Ok I pulled the trigger I had to buy it after all if it is complete rubbish Ebay and PayPal favors the buyer and I will send it back. As soon as I get it I will post Photo Samples Maybe even get ambitious and do a video review. Lenses Im excited most to use is Vivitar 17mm 3.5 or my Vivitar 28mm 2 Oh and like all of my pentax legacy glass
05-15-2013, 08:43 PM   #23
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QuoteOriginally posted by Sliver-Surfer Quote
Ok I pulled the trigger I had to buy it after all if it is complete rubbish Ebay and PayPal favors the buyer and I will send it back. As soon as I get it I will post Photo Samples Maybe even get ambitious and do a video review. Lenses Im excited most to use is Vivitar 17mm 3.5 or my Vivitar 28mm 2 Oh and like all of my pentax legacy glass
great, thank's a lot for that! I can't wait for your samples!
I have great hopes for this adapter, made by a company with a record of making decent optics why should it not perform just as well as the M.bones

Do you have a M42>Pentax K adapter? If so I'd be most curious to find out if it works on the focal reducer! I am afraid though that the focal reducer most likely won't have a lock for the M42 adapter and therefore the M42 adapter will rotate which makes use difficult unless one finds a way how to lock it in place.


Last edited by kuuan; 05-15-2013 at 11:22 PM. Reason: added M42 adapter question
05-16-2013, 04:46 AM   #24
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QuoteOriginally posted by kuuan Quote
great, thank's a lot for that! I can't wait for your samples!
I have great hopes for this adapter, made by a company with a record of making decent optics why should it not perform just as well as the M.bones

Do you have a M42>Pentax K adapter? If so I'd be most curious to find out if it works on the focal reducer! I am afraid though that the focal reducer most likely won't have a lock for the M42 adapter and therefore the M42 adapter will rotate which makes use difficult unless one finds a way how to lock it in place.
I do Have m42 adapters both the flange(no infinity) and no flange. It just shipped last night..Im curious how fast their expedited mail is...however any wait is a long wait.
05-16-2013, 05:09 AM   #25
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I just purchased the new NEX-3N body that is the smallest and lightest NEX and is the only one with on body zoom lever for the new compact 16-50mm (24-75mm eqiv) PZ OSS zoom that I have and I also have the 55-210mm OSS zoom so I just might get one to use with my fast F1.4 FF 24mm,35mm,50mm and 85mm lenses @F1.0.


another listing I see on ebay:
Focal Reducer Speed Booster Adapter Pentax K PK Mount Lens to Sony NEX 5R 3N 6 7 | eBay

05-16-2013, 06:12 AM   #26
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QuoteOriginally posted by jogiba Quote
FYI: I have purchased from both of these sellers in the past, and they are both reputable, but Roxsen seems to ship using a faster service by default (1 week vs. 4 weeks to Canada).
05-16-2013, 09:57 AM   #27
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QuoteOriginally posted by jogiba Quote
I just purchased the new NEX-3N body that is the smallest and lightest NEX and is the only one with on body zoom lever for the new compact 16-50mm (24-75mm eqiv) PZ OSS zoom
Congrats,

I think the 3N is a fantastic value. Especially at $50 off right now, for the kit. I've been trying to convince my coworker to get one.

I ended up ordering the FD mount version. Some people on DPReview have already received their adapters and are getting good results. It seems there are some internal reflections, but overall the quality is there. I don't mind a bit of flare and ghosting, it can look cool sometimes.
05-16-2013, 10:12 AM   #28
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QuoteOriginally posted by kenafein Quote
Some people on DPReview have already received their adapters and are getting good results. It seems there are some internal reflections, but overall the quality is there. I don't mind a bit of flare and ghosting, it can look cool sometimes.
Do you have a link to the thread with photos? I could search, but dpreviews forum search is worse than the one here!
05-16-2013, 10:39 AM   #29
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QuoteOriginally posted by panoguy Quote
Do you have a link to the thread with photos? I could search, but dpreviews forum search is worse than the one here!
http://www.dpreview.com/galleries/4489424077/photos/2555525/nikkor-with-zhongyi-lens-turbo

http://www.dpreview.com/forums/post/51447165

Last edited by kenafein; 05-16-2013 at 10:51 AM.
05-16-2013, 05:29 PM   #30
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Thanks! Hard to tell the advantages given the lens used (a Nikkor variable-aperture kit zoom), but if blue backflare is the only occasional problem, then it could really work well with the FA Limiteds!
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