Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
03-13-2014, 04:20 AM   #1
Veteran Member
konraDarnok's Avatar

Join Date: Aug 2007
Photos: Albums
Posts: 968
Sony a7 with focal reducer thread

A7 Pentax 40mm F2,8 Lensturbo FF-5687 | Flickr - Photo Sharing!

The above picture was taken with a Sony A7 with a 'full frame' 40mm 2.8 in conjunction with a Lens Turbo; the vignetting is not too bad, could certainly be fixed in post. Has anyone been investigating which 'full frame' lenses could benefit from some extra speed and field of view on a full frame camera?


Last edited by konraDarnok; 03-13-2014 at 10:10 AM. Reason: Edited for clarity
03-13-2014, 06:01 AM   #2
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
The focal reducer is only for full frame lenses used in APS-C mode on the Sony full frame VG900, A7 and A7r. I tried the Lens Turbo with MF Pentax 67 165mm F2.8 and it vignetted on my full frame VG900. I use the Lens Turbo on my APS-C Sony NEX-3N and it works great with full frame Pentax lenses.
03-13-2014, 06:17 AM   #3
Veteran Member
konraDarnok's Avatar

Join Date: Aug 2007
Photos: Albums
Posts: 968
Original Poster
QuoteOriginally posted by jogiba Quote
The focal reducer is only for full frame lenses used in APS-C mode

I'm interested in results for Full Frame mode, not APS-C mode. Like this:

Per analogia: A7 i obiektywy/adaptery nie kryj?ce FF (II) / A7 and non-FF lenses/adapters (II)
03-13-2014, 06:25 AM   #4
Banned




Join Date: Sep 2006
Location: Millstone,NJ
Posts: 6,491
I was testing with lens wide open so maybe closing the aperture might work . I know APS-C zoom lenses work in full frame mode without vignetting on the full frame Sony cameras when closed down a few stops like my Tamron 10-24mm zoom.

QuoteQuote:
But the advantages of the NEX 10-18mm are manifold! You basically get to move it between 12mm-17mm without seeing the ring around the outside. And yes, you get the full-frame goodness of the 36 megapixels of the Sony A7r! Thatís much wider than the 16-35mm. The distortion is pretty much exactly the same on both cameras, as you can see in the video review. Even better, the NEX lens is over 2x lighter, 3x cheaper, and a fraction of the size. Amazing! Iím not seeing any difference in the sharpness of the lens.

So this was a pretty big decision for me ó to switch to this lens when I fully anticipated using the 16-35mm until the new FE wide-angle lens for the Sony A7 launches later this year. I expect that will be a superior lens to both of these, although probably not as inexpensive as this NEX 10-18mm.
Sony 10-18mm Lens Review

QuoteQuote:
The Sony NEX 10-18mm on the Sony A7r

Here is a photo I took with the 10-18mm lens on the Sony A7r.


03-13-2014, 07:35 AM   #5
Pentaxian
jcdoss's Avatar

Join Date: Nov 2012
Location: Jasper, AR
Photos: Gallery | Albums
Posts: 3,327
I'm surprised this topic hasn't come up sooner. These adapters fit the A7/R, and most people have them if they're moving up from NEX. It looks like it might be a fun thing to try. I put the 10-17 FE on my NEX-6/Lens Turbo periodically just to make myself dizzy.
03-13-2014, 09:40 AM   #6
osv
Veteran Member




Join Date: Mar 2007
Location: So Cal
Photos: Gallery
Posts: 2,080
QuoteOriginally posted by konraDarnok Quote
I'm interested in results for Full Frame mode, not APS-C mode. Like this:

Per analogia: A7 i obiektywy/adaptery nie kryj?ce FF (II) / A7 and non-FF lenses/adapters (II)
the canon fdn lenses used in that link are full-frame lenses, not "non-ff lenses/adapters", as the page title says... maybe it's an english translation problem? because those lenses don't need a focal adapter, i can't see the logic behind adding another layer of glass, if that's what is happening there... of course, since we are looking at weird combos, lol...

in addition to using certain aps-c lenses on full-frame cameras, some aps film lenses will work on the a7/a7r... i tested it with ix-nikkor lenses from nikon pronea cameras:

Nikon IX-Nikkor APS film camera lenses mounted on Sony a7 a7r NEX e-mount cameras

i looked at the 30-60 lens there, that lens takes a full-frame shot with some vignetting, but it's usable... the better option for a cheap junk super-light zoom is the ix-nikkor 20-60 lens, because it gives you a usable 24mm focal length, on a full-frame camera... the 20-60 that i shot with had some possible focus distortion issues on the right hand side, but the center area was plenty sharp on the a7r... unfortunately that uneven frame issue means that i've basically struck out on both ix-nikkors.

here is that 20-60 pic, at 24mm focal length, unfortunately this forum won't take the full-size:
Attached Images
View Picture EXIF
ILCE-7R  Photo 
03-13-2014, 09:46 AM   #7
Veteran Member
LFLee's Avatar

Join Date: Aug 2009
Location: Southern California
Photos: Gallery | Albums
Posts: 2,292
The OP post is confusing initially, since focal reducer work on filling ff image circle on APSC size sensor. but I think OP means:

fitting FF image on FF sensor - essentially putting image circle bigger than FF onto the FF sensor. So a 35mm FF lens become a wider lens than 35mm...
of course in this case one would imagine vignette will occur.

Interesting!

If you put a P67 to K-mount, then a focal reducer of K to Sony M-mount, will you get MF image circle? like 105mm f2.4 become 52mm FF equivalent

03-13-2014, 10:05 AM   #8
Veteran Member
konraDarnok's Avatar

Join Date: Aug 2007
Photos: Albums
Posts: 968
Original Poster
QuoteOriginally posted by LFLee Quote
The OP post is confusing initially, since focal reducer work on filling ff image circle on APSC size sensor.

It's not APS-C. The 40mm 2.8 is on the A7 FF sensor with a lens turbo, which is why it's vignetting, although not all that badly. The next image in the Flickr series "A7 BIOMETAR 80mm F2,8 Lensturbo" vignettes heavily.

I don't know why people are confused, but they are. This is for FF lenses, being used with a focal reducer, on a FF camera.

Last edited by konraDarnok; 03-13-2014 at 10:12 AM.
03-13-2014, 10:07 AM   #9
Forum Member




Join Date: Apr 2013
Posts: 50
A7 plus medium format/full frame lenses
03-13-2014, 10:18 AM   #10
osv
Veteran Member




Join Date: Mar 2007
Location: So Cal
Photos: Gallery
Posts: 2,080
QuoteOriginally posted by konraDarnok Quote
I don't know why people are confused, but they are. This is for FF lenses, being used with a focal reducer, on a FF camera.
it's confusing for two reasons:
1) the page title "non-ff lenses/adapters" is wrong, it should read "non-ff adapters", since it's only using full-frame lenses.
2) deliberately causing vignetting like that is not logical, and the pictures don't show any desirable effect from doing it.

unless i'm missing something?
03-13-2014, 10:22 AM   #11
Veteran Member
konraDarnok's Avatar

Join Date: Aug 2007
Photos: Albums
Posts: 968
Original Poster
QuoteOriginally posted by osv Quote
it's confusing for two reasons:
1) the page title "non-ff lenses/adapters" is wrong, it should read "non-ff adapters", since it's only using full-frame lenses.
2) deliberately causing vignetting like that is not logical, and the pictures don't show any desirable effect from doing it.

unless i'm missing something?

Whatever the page title says "Sony A7, Lens Turbo, Canon FD 2/35mm @f/2.0, FF mode" is not very ambiguous if you ask me.

If you have no interest in the topic, don't participate.
03-13-2014, 10:26 AM   #12
osv
Veteran Member




Join Date: Mar 2007
Location: So Cal
Photos: Gallery
Posts: 2,080
QuoteOriginally posted by K-Rex Quote
https://www.youtube.com/watch?v=NXm_B1dSq0I
A7 plus medium format/full frame lenses
that was absolutely horrible, lol

isn't the focal booster for aps-c format? why put it on a full-frame sensor?

if you need vignetting, add it in post... i don't get it.
03-13-2014, 10:28 AM   #13
Forum Member




Join Date: Apr 2013
Posts: 50
If you put medium format glass on it, you should have the extra stop of light hitting the sensor, and a shallower depth of field.
03-13-2014, 10:38 AM   #14
osv
Veteran Member




Join Date: Mar 2007
Location: So Cal
Photos: Gallery
Posts: 2,080
i could certainly see that happening with a focal booster that's designed for a full-frame sensor... does anyone make such a thing?

bigger sensors mean shallower depth of field, as compared to a crop sensor, so you already have a shallower dof advantage without jumping through all those hoops.
03-13-2014, 10:42 AM   #15
Forum Member




Join Date: Apr 2013
Posts: 50
QuoteOriginally posted by osv Quote
i could certainly see that happening with a focal booster that's designed for a full-frame sensor... does anyone make such a thing?

bigger sensors mean shallower depth of field, as compared to a crop sensor, so you already have a shallower dof advantage without jumping through all those hoops.
"Full frame 35mm" is actually a crop sensor. The depth of field is narrower with medium format or large format camera. Please take a 645/ or 6X7 for a spin and come back and tell me there isn't a difference.
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!
40mm, a7, adapter, booster, camera, circle, crop, ff, format, frame, full-frame, image, lens, lenses, mf, pentax, people, sensor, sony a7, turbo
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sony A7 with Pentax Lenses: A Review Adam Non-Pentax Cameras: Canon, Nikon, etc. 35 10-14-2016 05:35 PM
$199 focal reducer speed booster adapter Pentax PK K to Sony NEX jogiba Pentax Price Watch 91 12-07-2014 09:19 AM
What Weíre Finding Wrong With the Sony A7 and A7r So Far interested_observer Non-Pentax Cameras: Canon, Nikon, etc. 104 05-12-2014 10:43 AM
Serious problem detected with Sony A7/A7r : light leak andre-mz5 Non-Pentax Cameras: Canon, Nikon, etc. 84 03-24-2014 07:40 PM
Focal length reducer for 645 lenses yusuf Pentax SLR Lens Discussion 10 02-06-2014 05:00 PM



All times are GMT -7. The time now is 01:33 AM. | See also: NikonForums.com, CanonForums.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