chipvn
Senior Member
A very good lens! Nice view, bro!
Sony A7/(r) image sharing thread #2
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Pentax FA20/2.8 by jenkwang, on FlickrA7+Pentax FA20/2.8
Had a chance to try out this lens.
Smaller than the FD20/2.8 SSC I have and more punchy o/p.
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chipvn
Senior Member
Thinking to buy this lens previously to use on film camera but I just felt that the distortion is a bit too high for my taste for a wide angle lens on FF. How about the corner performance?
wondering if any of you have tips for manual focusing on moving objects (kids or street shooting), especially at the tele range or at large apertures (f2?). I read stuff like zone focusing but it doesn't help for these scenarios ? pre-focus then sometimes also won't be correctly focused on the eyes
recently acquired a pentax 135mm and I'm a mf newbie, by the time I focus the subject will already leave the frame :cry:
recently acquired a pentax 135mm and I'm a mf newbie, by the time I focus the subject will already leave the frame :cry:
MHO, if you already got CV21 Ultron, then no point.
Ultron is sharper (but not as punchy as the Pentax) and better corners (but then its 21mm and not 20mm)
f1.8 vs f2.8 too for those wide but a bit less DOF shots that only the Ultron can pull off.
Of course the Ultron is also much more expensive than the FA20/2.8 and the FA has AF on a Pentax camera.
The only weakness of the FA20/2.8 from my limited try was the far edges (maybe the last 1/10 of the frame).
The rest was very strong, very punchy with nice contrast and colors (imo, better than Ultron and FD20 in this respect).
Distortion, depends on user and genre (landscapes, usually ok; cityscapes and particular about it then maybe not)(pretty moot to talk about it if you shoot largely ignoring keystone distortion too imho)
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Tiredofallthese
Senior Member
MHO, if you already got CV21 Ultron, then no point.
Ultron is sharper (but not as punchy as the Pentax) and better corners (but then its 21mm and not 20mm)
f1.8 vs f2.8 too for those wide but a bit less DOF shots that only the Ultron can pull off.
Of course the Ultron is also much more expensive than the FA20/2.8 and the FA has AF on a Pentax camera.
The only weakness of the FA20/2.8 from my limited try was the far edges (maybe the last 1/10 of the frame).
The rest was very strong, very punchy with nice contrast and colors (imo, better than Ultron and FD20 in this respect).
Distortion, depends on user and genre (landscapes, usually ok; cityscapes and particular about it then maybe not)(pretty moot to talk about it if you shoot largely ignoring keystone distortion too imho)
Haizz...regretted sold it....true its a nice lens...
chipvn
Senior Member
From the JK photo above, if I'm not wrong, you can see the distortion is quite bad! The bottom portion looks wavy and that's one is very difficult to correct. That's what I've seen from my friend film camera before as well. On cropped, it not too bad although still distort more than the DA21. Actually I still want to stay with Pentax so sometime still want to buy one AF fixed wide to wait for their FF (if it happen to be true)
Thanks JK for the info.
Thanks JK for the info.
Tiredofallthese
Senior Member
Thats old 20mm lenses for you.
All of them have it (and if you look at the Photozone tests, even the Distagon T*21/2.8 has it),
Certainly no free lunch for the 20mm esp taking into account size, weight, price.
I actually doubt there is a legacy wide 20mmm that is very distortion free and AF.
Maybe the CZJ Flektogon 20/4 perhaps (said to be 0 distortion), but poorer coatings and MF ?
Bro, I am not an expert using MF lenses but I think it's hard to manual focus with a tele (135mm) and shallow DOF (f2). At 135mm ad f2.8, the DOF is only 23cm (based on an app I used). Your margin for error is very very small.
Edit: I meant margin for error on moving objects.
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Does anyone shoot in burst mode (and adjust focus constantly within a 10cm range maybe) and pray at least 1 frame is sharp? :embrass: Not sure how good it works with just 5fps on the a7 though..
chipvn
Senior Member
I understand that most wide lenses have distortion but more than 2% even on cropped sensor is a bit too much!Thats old 20mm lenses for you.
All of them have it (and if you look at the Photozone tests, even the Distagon T*21/2.8 has it),
Certainly no free lunch for the 20mm esp taking into account size, weight, price.
I actually doubt there is a legacy wide 20mmm that is very distortion free and AF.
Maybe the CZJ Flektogon 20/4 perhaps (said to be 0 distortion), but poorer coatings and MF ?
Look at the A7II just launched, I think I will stop hoping on anything better from Pentax that can change the game! It will be too late, even in case that it can be better. Haizzz ...
DSC06649_2400 by jenkwang, on Flickr
A7+CV12/5.6
I understand that most wide lenses have distortion but more than 2% even on cropped sensor is a bit too much!
Look at the A7II just launched, I think I will stop hoping on anything better from Pentax that can change the game! It will be too late, even in case that it can be better. Haizzz ...
Actually, as I mentioned, most of the 20mm are like that sort of very new ones (ie. >2%, mustache type).
This includes the Minolta A mount and the Nikon AF 20/2.8.
The Canon Ef20/2.8 is the better one at ~1.5%
Do check out photozone for the details if you need.
RF UWA lenses with symmetric designes are supposed to offer less complicated distortion types, but more prob so far on A7 (except CV12 and 21).
I do think modern optics with CAD, new coatings and more asph elements are the way for technically better UWA and long Tele. (not considering price)
A7II?
For me, the current A7 issues need to be addressed and its not IBIS.
Sensor reflection; Sensor stack thickness being the two key ones which is tech related.
Others are in the interface (ie. can't turn off lcd (it just turns 'black' not off; rigid bracketing options; no timer release for bracketing; menu digging for Remote ON/OFF and "Settings affect Display" for strobing purposes; too much magnification for MF)
Color is another thing too.
So a lot of things remains to be seen.
Its a better option over A7 for the new buyer, but not that big a deal for the current user imo.
Its going to shake the foundations of the traditional DSLR makers for sure. (at least for the generalist enthusiast w/o special needs)
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