Sony A7 vs Lens Turbo (Speed booster")

[Rawfa]

These are not scientific tests at all (neither are they fair, because the lens turbo is not as wide and because we are comparing a cropped sensor to a full frame one) but I thought I'd just throw them out there for the sake of it.

What I did was simply to take my Sony A7, place it on a tripod, set all settings the same and test my Pentax 28mm f2.8, 50mm 1.4 and 85mm f2.0 with the Lens Turbo in APS-C mode (the generic speed booster) and with a regular Pentax PK adapter in full frame mode. All shots were taken wide open and I connected the camera to a 32inch HDTV to focus (I used the camera's full magnification assist). It really surprised me that the A7 was not able to achieve full focus and the lens turbo was. The corners are bad in both cases as is the overall IQ with THESE PARTICULAR LENSES wide open.

Sony A7 with regular Pentax PK adapter and 28mm f2.8

Full resolution http://farm3.staticflickr.com/2852/12075319586_36ded90341_o.jpg

Sony A7 with lens turbo and 28mm f2.8

Full resolution
http://farm8.staticflickr.com/7302/12075343386_d7fa33bd3a_o.jpg

Sony A7 with regular Pentax PK adapter and 50mm f1.4

Full Resolution
http://farm4.staticflickr.com/3730/12075021533_49397f1deb_o.jpg

Sony A7 with lens turbo and 50mm f1.4

Full Resolution http://farm8.staticflickr.com/7304/12074735355_ab118befc8_o.jpg

Sony A7 with regular Pentax PK adapter and 85mm f2.0

Full Resolution http://farm8.staticflickr.com/7325/12075169204_fd2f8254bd_o.jpg

Sony A7 with lens turbo and 85mm f2.0

Full resolution http://farm8.staticflickr.com/7458/12075428866_2802534eb4_o.jpg

 

[ken_vs_ryu]

What's your conclusion about the centers?

 

[OlliL]

Hi Rafael,

Thanks for the comparison.

I'd be much more interested in an A7 VS a Nex (insert number here) + Lens turbo comparison tho.

Do you have a Nex on hand to do this?
I'm thinking of either an A7, or a NEX6 (7, a6000...) with such an adapter.

Best
Oliver

 

[mazor]

yes and better yet why not try it with the Metabones speed booster rather a generic lens turbo adapter.

 

[OlliL]

yes and better yet why not try it with the Metabones speed booster rather a generic lens turbo adapter.

Cough, cough, price?!

But yes, comparing the Nex VS A7 (used) prices, a MB Speebooster would put them in the same ball park.

 

[kienchil]

Cough, cough, price?!

But yes, comparing the Nex VS A7 (used) prices, a MB Speebooster would put them in the same ball park.

I have a NEX 5R and MB Speedbooster and A7R

I have to say there is no comparison between the two, in every single way the A7R outshines the 5R + SB, with the same lenses. There is less of a difference at low ISO but at high ISO A7R is better, EVEN taking into account the extra stop of light that the speedbooster gives the 5R.

Speedbooster on the A7R in crop mode is kind of a good middle ground, useful for lowlight situations where I don't need the full 36mp but want the extra stop of light the speedbooster gives. Still better than the 5R noise wise.

Maybe a closer comparison would be the NEX-7 vs A7R

Theres a good blog here Photototo that explores this comparison.

 

[Ben Rubinstein]

Which versions of Pentax lenses? I have the SMC Takumar 28mm, Super Takumar 35mm and 50mm 1.4 and the Pentax M 85mm f2. I just bought a Pentax M 24mm f2.8 yesterday. I have the novoflex adaptor for all. On the A7r the 28mm and 35mm have corners you would imagine, typical for lenses of the age, the 50mm was incredible at f8, corner to corner and the 85mm is a very sharp lens stopped down but I haven't tested corners on what I use as a portrait lens. I've bought the 24mm as a fun and cheap stop gap solution as I work out whether to buy the Zeiss 21mm, the Nikon 14-24 or wait for the sony E mount wide angle solution. I need a really good wide angle solution for commercial work.

 

[Rawfa]

Metabones doesn´t have Pentax PK Speedbooster yet.
I don´t have any APS-C NEX camera to test with the lens turbo against the A7.
The 28mm and the 50mm are SMC. The 35mm and 85mm are some offbrand lenses. I have a 35mm f2.0 that is almost perfect though (with the exception of some very very sublte vingeting).
Anyway, as much as I like Pentax I´ve started using Canon FDs, which are bigger and I´ve been getting great results.

 

[mazor]

Metabones doesn´t have Pentax PK Speedbooster yet.
I don´t have any APS-C NEX camera to test with the lens turbo against the A7.
The 28mm and the 50mm are SMC. The 35mm and 85mm are some offbrand lenses. I have a 35mm f2.0 that is almost perfect though (with the exception of some very very sublte vingeting).
Anyway, as much as I like Pentax I´ve started using Canon FDs, which are bigger and I´ve been getting great results.

I think the best Metabones speed booster to get would be the EF- emount and then carefully add dumb non electronic adapters on top. So to get Pentax PK onto speedbooster, one just needs a pentax K to EF adapter and mount that onto the EF- e mount speed booster.

 

[kienchil]

I think the best Metabones speed booster to get would be the EF- emount and then carefully add dumb non electronic adapters on top. So to get Pentax PK onto speedbooster, one just needs a pentax K to EF adapter and mount that onto the EF- e mount speed booster.

Yes the Metabones EF Speedbooster is easily adaptable I have OM, PK C/Y and Nikkor lenses that adapt well with just a metal "ring" adapter and they are cheap (5 USD) and plentiful because on the amount of Canon systems around.