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07-04-2019, 11:18 PM   #1
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DA lenses on an A7ii?

Hi!

I'm really considering buying a used A7ii by the end of the summer to replace my K-50. I love the idea of mirrorless and have really enjoyed my short time using a Sony full frame. I see that there are adapters for Pentax lenses online, but none seem to autofocus... Do no autofocus adapters exist? Also, if my lenses (Sigma 17-50 2.8, DA* 50-135, etc.) don't have an aperture ring, what will happen when I try to take pictures? The only lens I have with an aperture ring is some old 50 1.7.

Any advice is greatly appreciated! I'm thinking it's either this or the KP.

Also, I do understand that my lenses are APS-C and I would need to use crop mode.

07-04-2019, 11:57 PM - 1 Like   #2
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QuoteOriginally posted by roberts_camera Quote
Hi!

I'm really considering buying a used A7ii by the end of the summer to replace my K-50. I love the idea of mirrorless and have really enjoyed my short time using a Sony full frame. I see that there are adapters for Pentax lenses online, but none seem to autofocus... Do no autofocus adapters exist? Also, if my lenses (Sigma 17-50 2.8, DA* 50-135, etc.) don't have an aperture ring, what will happen when I try to take pictures? The only lens I have with an aperture ring is some old 50 1.7.

Any advice is greatly appreciated! I'm thinking it's either this or the KP.

Also, I do understand that my lenses are APS-C and I would need to use crop mode.
It seems there're no autofocus K-E adapters yet. Also it seems that a lense without an aperture ring will operate wide open (f2.8 in your case). I would consider either getting a used K-1 to use Pentax lenses or keep current Pentax APS-C cameras and lenses, go with Sony A7ii and look at new Samyang AF lenses for E mount which are cheaper than Sony offerings and seem to be not bad at all.
07-05-2019, 01:16 AM   #3
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QuoteOriginally posted by roberts_camera Quote
Hi!

I'm really considering buying a used A7ii by the end of the summer to replace my K-50. I love the idea of mirrorless and have really enjoyed my short time using a Sony full frame. I see that there are adapters for Pentax lenses online, but none seem to autofocus... Do no autofocus adapters exist? Also, if my lenses (Sigma 17-50 2.8, DA* 50-135, etc.) don't have an aperture ring, what will happen when I try to take pictures? The only lens I have with an aperture ring is some old 50 1.7.

Any advice is greatly appreciated! I'm thinking it's either this or the KP.

Also, I do understand that my lenses are APS-C and I would need to use crop mode.
Check out this article to see which lenses cover FF and which ones will need to be limited to crop mode only:

Full Frame Coverage of DA Lenses: Comprehensive Test - Gear Guides | PentaxForums.com

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07-05-2019, 02:37 AM - 2 Likes   #4
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Your DA 35 and DA 50 would cover a full frame sensor, at least passably. It is unlikely that there will ever be adapters that allow for auto focus of screw driven k mount lenses for MILC cameras. Such an adapter would have to be pretty complex. You will have to search for one that allows for aperture control via the adapter. Unfortunately, I think Coiseam is wrong and if you use a dumb adapter with your lenses the default setting is stopped all the way down -- f22 or some such aperture. This is why the aperture block situation produces such dark photos.

07-05-2019, 03:54 AM   #5
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QuoteOriginally posted by Rondec Quote
if you use a dumb adapter with your lenses the default setting is stopped all the way down -- f22 or some such aperture. This is why the aperture block situation produces such dark photos.
Correct. However, there are inexpensive adapters available with a control ring to operate the lens diaphragm. I have one - I think it's a Fotodiox model, but I'm not certain of that. Used carefully, it can provide limited control of the lens aperture, but it's impossible to know the exact setting... You can judge by setting exposure accurately with the lens wide open, then watch how exposure is affected as you slowly close it down. Pretty clunky, but it works. That said, I don't actively use any of my DA lenses on my A7 MkII... It's simply not convenient.
07-05-2019, 04:27 AM   #6
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I think the only auto-focusing adapters to use non-native lenses on mirrorless cameras are to use EOS lenses on various mirrorless cameras.

For my Fujifilm cameras I can use DA adapters if I use the adapter which allows some control of the aperture (most adapters don't). It's a little basic but I think allows around seven or eight aperture settings from wide open to fully closed (f/22??). The DA limited lenses work very well on Fujifilm cameras - they're easy to use and it's a combination that provides great image quality.

If most of your lenses are DA and you've got your heart set on using them on mirrorless then you can ave yourself a lot of money by getting a camera with a sensor smaller than FF. If it were me, I think I'd get rid of the DA lenses if I moved to any kind of FF and make full use of the sensor. Of course, it would really pain me, especially in the case of the DA limiteds, but it wouldn't make sense to keep them. I think I'd make an exception for the DA 35mm limited though.
07-05-2019, 05:40 AM - 2 Likes   #7
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Sounds like a lot of messing around for nothing. Why not just sell what you have and buy what you need?
07-05-2019, 08:42 AM   #8
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QuoteOriginally posted by normhead Quote
Sounds like a lot of messing around for nothing. Why not just sell what you have and buy what you need?
Or keep what you have and buy more!

If I were to move to Sony mirrorless (it has been contemplated), I would definitely keep my crop-format K-mount kit.


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07-05-2019, 09:08 AM   #9
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Thanks for all of the input! I've considered selling what I have, it just sounds difficult because I would be able to probably buy the Sony body and maybe just two lenses or so, if that. And I could keep my current body and just buy Sony gear in addition, but that's kinda hard to justify as a student. I have an internship this summer and a co-op in the fall so I'll be making decent money, but it's still hard to make multiple big purchases. Sounds like I'll look a bit more into the KP!
07-05-2019, 02:51 PM - 1 Like   #10
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QuoteOriginally posted by roberts_camera Quote
Thanks for all of the input! I've considered selling what I have, it just sounds difficult because I would be able to probably buy the Sony body and maybe just two lenses or so, if that. And I could keep my current body and just buy Sony gear in addition, but that's kinda hard to justify as a student. I have an internship this summer and a co-op in the fall so I'll be making decent money, but it's still hard to make multiple big purchases. Sounds like I'll look a bit more into the KP!
I think you're wise to look into the KP.

Different bodies and systems are all well and good, but what matters most is the glass. If you're fortunate enough to find a few lenses that you really like, that's gold dust. Treasure those lenses, and use the system they were designed for. When all's said and done, most camera bodies (however many bells and whistles they offer) do much the same things, with some advantages and disadvantages over their competitors. What you can do with one body, you can more-or-less achieve with any other, excepting certain specialist applications. But there's individual character in lenses that won't be easily replicated by picking something of the same or similar focal length from another manufacturer. I'm not bowled over by every single Pentax lens I own, but I've grown to love several of them, and that's one of many reasons that I wouldn't want to switch.

On a related note, I maintain two systems side by side... Pentax K-mount (all APS-C gear), and Sony A-mount - the latter, because I bought a Hasselblad HV (re-bodied / re-badged Sony A99) a few years ago, just for the fun of it. I've had to kit myself out with a number of A-mount lenses so that I can cover the same applications that are important to me with my Pentax gear. I have no regrets buying the HV or the lenses for it, but it's an awfully expensive luxury that has no logical justification. I certainly wouldn't recommend that others invest in two entirely different systems if just one of those could cover all of their photographic needs (and that's usually the case). It's far better to commit to just one system...
07-05-2019, 03:54 PM   #11
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QuoteOriginally posted by roberts_camera Quote
I'm really considering buying a used A7ii
Techart PRO Leica M – Sony E Autofocus Adapter – TECHART Adapters

QuoteOriginally posted by roberts_camera Quote
Do no autofocus adapters exist?
Yes,there are 2.Fotodiox have copied the TechartPro.

Both say that their adapters shouldn't be used with lenses above a certain weight.However, theres a YT video showing a Nikon 400mm f2.8 functioning fine.Its 3kgs or thereabouts.

Also Fotodiox says that their adapter cant be updated via firmware,strangely it can by doing it with the Techart firmware(6.0 is the latest).

Fotodiox is a fair amount cheaper too, last time I looked.Search YT,theres lots to look at.

The Pentax M series lenses would be ideal for their lightweight compactness,no need for any E mounts.
07-05-2019, 04:07 PM - 1 Like   #12
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QuoteOriginally posted by surfar Quote
Techart PRO Leica M – Sony E Autofocus Adapter – TECHART Adapters



Yes,there are 2.Fotodiox have copied the TechartPro.

Both say that their adapters shouldn't be used with lenses above a certain weight.However, theres a YT video showing a Nikon 400mm f2.8 functioning fine.Its 3kgs or thereabouts.

Also Fotodiox says that their adapter cant be updated via firmware,strangely it can by doing it with the Techart firmware(6.0 is the latest).

Fotodiox is a fair amount cheaper too, last time I looked.Search YT,theres lots to look at.

The Pentax M series lenses would be ideal for their lightweight compactness,no need for any E mounts.
I have to comment here, as I own the genuine Techart Pro adapter...

It works. On longer lenses (beyond 50mm or so), the range of back and forth movement isn't enough to cover the entire focusing range, and so one must pre-focus closer to the subject. Build quality is quite good, but because of the way the mechanism is designed, it develops wobble over a prolonged period of use, and that leads to lateral mis-alignment of the lens. Performance (speed) is OK, but hardly impressive. As I said, it does work - but it's not amazing, and doesn't compare to the native AF of the system lenses were designed for. The native mount for the adapter is Leica M, so attaching other lenses requires additional adapters... but, the Techart Pro is very fussy about the way these adapters are made. Many won't lock into place because of the adapter's locking slot design (IMHO, an intentional design element to force folks into buying Techart's own over-priced adapters). Lastly, the method of programming data into the mount for EXIF purposes is just plain weird.

I bought the adapter as I thought it would be fun and useful with a range of vintage glass I own. Shortly after buying it, I realised that - for me - it's more trouble than it's worth, and I'm better off sticking with manual focusing. Mine will end up on eBay when I can get round to photographing and listing it...
07-05-2019, 04:08 PM   #13
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You should have got the Fotodiox!
07-05-2019, 04:11 PM   #14
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QuoteOriginally posted by surfar Quote
You should have got the Fotodiox!
Both just as bad, frankly, from everything I've read. And the Fotodiox is a commercial rip-off of the original and TechArt's IP, so I wouldn't be too comfortable with it anyway... That's almost like buying a high quality fake Rolex...

Have you personally used the Fotodiox adapter? Or the TechArt one?
07-05-2019, 04:11 PM - 1 Like   #15
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QuoteOriginally posted by roberts_camera Quote
is some old 50 1.7.
Theres a report about the A 35-105mm in the lens section.One commentator is using an A7 manually.Focus peaking is a great aid.

---------- Post added 07-06-19 at 10:17 AM ----------

QuoteOriginally posted by BigMackCam Quote
Both just as bad, frankly. And the Fotodiox is a commercial rip-off of the original and TechArt's IP
IP doesn't exist for certain companies!

Your experience is the first with any negativity I've heard, but I considered A7 and A7ii then bought a K-1 which I'm still happy with.
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