Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
  
$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




Views: 19,269
06-18-2013, 06:48 AM   #76
Site Supporter




Join Date: Sep 2011
Posts: 1,239
QuoteOriginally posted by dcshooter Quote
Seriously, though, I think I recall reading on another forum that the Metabones guys had stated that they weren't able to successfully push their design past a 50% reduction. So while a Q mount item would be possible, it would be only a partial reduction. Given the limited low light capabilities of the Q sensor, this still might be useful, but the gains might also be offset by the reduction in sharpness caused by the added glass.
My dream camera if I could put myself in a pentax engineers shoes and build my own. Mirrorles pentax K01-2.0, slimmer front to back body, interchangeable removeable PKA-body adapter, with optional Speed booster PKA-body WR adapter . Electronic viewfinder a must

06-18-2013, 08:18 AM   #77
Veteran Member
devorama's Avatar

Join Date: Apr 2009
Location: Chicago, IL
Photos: Gallery | Albums
Posts: 638
I was doing some quick testing of the Lens Turbo and my Pentax 50mm F/1.2 lens. At F/2.8, using the Lens Turbo vs a regular lens adapter (with no glass), it appears that a similarly composed image will gain about 2/3 stop of light with the lens turbo. However, if you are using a lens that vignettes heavily, you won't gain 2/3 stop. Using the lens at F/1.2 and multi-segment metering, the NEX-3 I was using metered the same exposure with or without the Lens Turbo. Switching to Spot Metering gave me back 1/3 stop though. Kinda interesting. But if you really want to use the Lens Turbo to get better low light abilities, you may not really be gaining much. You'd probably be shooting your lenses wide open already, which means the part of the image circle you're now capturing will be heavily vignetted.
06-18-2013, 08:35 AM   #78
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
Original Poster
QuoteOriginally posted by VisualDarkness Quote
Hey, I want one for my Q! Are you listening Metabone or random Chinese makers?
Meade makes a F3.3 focal reducer ( 100mm = 33mm ) F10 = F3.3.
Meade f/3.3 CCD Focal Reducer/Field Flattener and Variable T-Adapter - Telescope Accessories at Telescopes


Meade F3.3 Focal Reducer on Nikon D200 APS-C. On the Q it will not vignette

Last edited by jogiba; 06-18-2013 at 08:42 AM.
06-18-2013, 09:01 AM   #79
Pentaxian
konraDarnok's Avatar

Join Date: Aug 2007
Photos: Albums
Posts: 960
QuoteOriginally posted by devorama Quote
I was doing some quick testing of the Lens Turbo and my Pentax 50mm F/1.2 lens. At F/2.8, using the Lens Turbo vs a regular lens adapter (with no glass), it appears that a similarly composed image will gain about 2/3 stop of light with the lens turbo. However, if you are using a lens that vignettes heavily, you won't gain 2/3 stop. Using the lens at F/1.2 and multi-segment metering, the NEX-3 I was using metered the same exposure with or without the Lens Turbo. Switching to Spot Metering gave me back 1/3 stop though. Kinda interesting. But if you really want to use the Lens Turbo to get better low light abilities, you may not really be gaining much. You'd probably be shooting your lenses wide open already, which means the part of the image circle you're now capturing will be heavily vignetted.

mind posting a side by side? I'm curious how it effects the field of view and the depth of field.

06-18-2013, 04:13 PM   #80
Marketplace Reseller
dcshooter's Avatar

Join Date: Jan 2011
Location: Washington DC
Photos: Gallery | Albums
Posts: 4,113
Interesting idea, but I'd wonder how such a design would handle screw drive lenses. The AF motor would either have to be in the main body (possibly increasing thickness) and pass through the secondary K adapter via a mechanical linkage (possibly slowing AF even more than it already is), or the motor would have to be in the adapter itself, meaning that native K-01-2.0 lenses would have to be in-lens (e.g. SDM) only, ruling out tiny pancakes and the like.

QuoteOriginally posted by Sliver-Surfer Quote
My dream camera if I could put myself in a pentax engineers shoes and build my own. Mirrorles pentax K01-2.0, slimmer front to back body, interchangeable removeable PKA-body adapter, with optional Speed booster PKA-body WR adapter . Electronic viewfinder a must
06-19-2013, 07:12 AM   #81
Junior Member




Join Date: Mar 2011
Location: Germany
Posts: 46
QuoteOriginally posted by Sliver-Surfer Quote
My dream camera if I could put myself in a pentax engineers shoes and build my own. Mirrorles pentax K01-2.0, slimmer front to back body, interchangeable removeable PKA-body adapter, with optional Speed booster PKA-body WR adapter . Electronic viewfinder a must
Great idea! I must not have a EVF... Can live without it on my K-01 very well...
06-19-2013, 09:25 AM   #82
Site Supporter




Join Date: Sep 2011
Posts: 1,239
QuoteOriginally posted by jedie Quote
Great idea! I must not have a EVF... Can live without it on my K-01 very well...
ok then a optional plug in EVF because on a sunny day it is fantastic to have one
06-23-2013, 08:51 PM   #83
Veteran Member
devorama's Avatar

Join Date: Apr 2009
Location: Chicago, IL
Photos: Gallery | Albums
Posts: 638
QuoteOriginally posted by konraDarnok Quote
mind posting a side by side? I'm curious how it effects the field of view and the depth of field.
I created a new thread for this because I figured other people might be interested too.

Evaluting the Lens Turbo

06-27-2013, 01:22 PM   #84
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
All these shots seem soft as all get out. Disappointing.
06-27-2013, 01:59 PM   #85
Site Supporter




Join Date: Sep 2011
Posts: 1,239
QuoteOriginally posted by rparmar Quote
All these shots seem soft as all get out. Disappointing.
They are samples of how the turbo looks straight out of the camera. Most of these shots are not sharpened using Post Processing and are done wide open on fast lenses.
IMHO too much PP sharpening usually will ruin the natural look of a picture
Ill take some shots with a sharp lens closed down for you

Last edited by Sliver-Surfer; 06-27-2013 at 02:14 PM.
06-27-2013, 10:01 PM   #86
Veteran Member
devorama's Avatar

Join Date: Apr 2009
Location: Chicago, IL
Photos: Gallery | Albums
Posts: 638
QuoteOriginally posted by Sliver-Surfer Quote
They are samples of how the turbo looks straight out of the camera. Most of these shots are not sharpened using Post Processing and are done wide open on fast lenses.
IMHO too much PP sharpening usually will ruin the natural look of a picture
Ill take some shots with a sharp lens closed down for you
Yeah, I mean you have to look at the relative sharpness I guess. I could stop down the lens for more sharpness, but then I'd have a much deeper DoF. That kinda defeats the purpose for me.
06-28-2013, 09:38 AM   #87
Veteran Member




Join Date: May 2011
Location: Southern California
Photos: Albums
Posts: 4,082
The price of the adapter is down to 166, from Roxen, on eBay.
06-28-2013, 10:07 AM   #88
Site Supporter




Join Date: Sep 2011
Posts: 1,239
Pentax K strong Backlight f1.8 Nice effect I think No Post Proccessing at all Ill get to some stopped down soon..Im just felling portraity today
Attached Images
View Picture EXIF
NEX-5N  Photo 
06-28-2013, 07:32 PM   #89
Veteran Member
rparmar's Avatar

Join Date: Jan 2008
Photos: Gallery
Posts: 8,783
QuoteOriginally posted by Sliver-Surfer Quote
They are samples of how the turbo looks straight out of the camera. Most of these shots are not sharpened using Post Processing and are done wide open on fast lenses.
IMHO too much PP sharpening usually will ruin the natural look of a picture
Ill take some shots with a sharp lens closed down for you
PP is not the issue. These shots are poor under any circumstances. Researching further I have found side-by-side tests that confirm that these knock-off adapters are quite bad optically. I guess I'll wait for Metabones to bring out a K adapter. That'll give me more time to save my pennies.
06-28-2013, 07:56 PM   #90
Marketplace Reseller
dcshooter's Avatar

Join Date: Jan 2011
Location: Washington DC
Photos: Gallery | Albums
Posts: 4,113
Eh, it's really tough to tell an image's true quality on this forum. Unfortunately the forum software (which is not designed specifically for a photo-oriented site) does a really poor job at preserving the detail (and often color and contrast) in images that it resizes/compresses. The way around this is to post originals smaller than 800px on the long dimension, which the resizing software will ignore, or to link images posted elsewhere. It's also always useful to include a 100% crop. And if you are really serious about judging quality, you should PM an image's original poster and ask for an original, full-size version.

This shortcoming is really a shame, since I see picture after picture on this forum that give no clue to true image quality, yet forum members are willing to engage in huge, misguided fights over the supposed quality they demonstrate for various lenses/cameras.


QuoteOriginally posted by rparmar Quote
PP is not the issue. These shots are poor under any circumstances. Researching further I have found side-by-side tests that confirm that these knock-off adapters are quite bad optically. I guess I'll wait for Metabones to bring out a K adapter. That'll give me more time to save my pennies.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
50mm, adapter, aperture, booster, lens, nex, pentax deals, pk, sony
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Speed Booster Adapter Winder Non-Pentax Cameras: Canon, Nikon, etc. 92 04-27-2013 12:11 AM
Pentax PK K lens to Sony Alpha A MA mount adapter romansolar Troubleshooting and Beginner Help 8 11-17-2012 04:28 AM
FOCAL REDUCER? Questions for astrophotographers RioRico Pentax SLR Lens Discussion 4 08-03-2011 08:33 PM
For Sale - Sold: PK adapter to NEX (Worldwide) Aegon Sold Items 3 09-09-2010 05:47 AM
Pentax adapter for Sony NEX possible? yoshizuki Pentax News and Rumors 18 05-22-2010 10:15 AM



All times are GMT -7. The time now is 08:26 AM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top