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Author Topic: Sony Alpha 7 and lenses...  (Read 8112 times)
MatthewCromer
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« Reply #20 on: October 18, 2013, 09:48:43 AM »
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The lens adapter issue is ridiculously overblown.  In the real world, you are using liveview with adapted lenses and manual focus.  Unless the adapter has hideous slop in its proportions, you'll be able to get very high quality results.
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Jim Pascoe
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« Reply #21 on: October 18, 2013, 11:42:11 AM »
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In my humble opinion I think Sony are heading in the right direction here.  The EVF aspect is what appeals to me as much as anything else.  Much as I love a really good optical VF, the EVF has many advantages, not least when shooting any video, which more people are using these cameras for now.  The Panasonic GH2 is a joy to use hand-held for shooting video on the run, where the OVF on a 5D for example forces one to shoot at arms length or on a tripod.  I would love to use a full frame Canon at eye-level with an EVF.  I am sure that in the very near future almost all DSLR's will be EVF.

Jim
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Manoli
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« Reply #22 on: October 18, 2013, 12:06:13 PM »
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But as a backup camera, you have to have a whole extra set of lenses unless you're using a converter ...

There's no doubt in my mind that the big test for this new Sony series is going to be whether or not they, or others, can produce stellar native wide-angles. 35mm and down (wider). It's no coincidence that Fujifilm introduced 3 primes and only one standard zoom when they introduced the x-trans series, followed swiftly by two ultra wides (14 & 27) plus two Zeiss (12 & 32) Touits.

The difficulty with these cameras is the large incident angle of incoming rays hitting the sensor - thus the inadequate performance of 'wides' with an adapter. From 'normal' and up, the exit pupil is further from the sensor surface and the incident angle is not as large. On APS-C bodies adapters work, how successful they'll be on FF - I don't know. But if they don't, the appeal to many will be diluted.

One reason we probably have not seen an UWA lens from Sony...it's going to be difficult to get good peripheral performance even with the new micro lenses.

+1

I am sure that in the very near future almost all DSLR's will be EVF.

+1
« Last Edit: October 18, 2013, 12:30:36 PM by Manoli » Logged
ErikKaffehr
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« Reply #23 on: October 18, 2013, 12:56:21 PM »
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Hi,

I don't see a problem with UWA lenses. You can put a Samyang 14/2.8, Zeiss 15/2.8, or Nikon 14-24/2.8 on almost any camera. Those are telecentric designs, of course, but there is nothing to hinder the use of telecentric lenses on Alpha 7. Problem is that telecentric designs tend to be large and heavy.

Best regards
Erik


I can't agree with this

Putting a great lens on your camera via an adapter might still be better than an average native-mount lens. On the other hand, that great lens certainly wouldn’t be as good as it would be on its native-mount camera.


Makes no sense. A native mount lens will make the rear elements sit very close to the sensor. An adaptor increases the sensor to element distance. Vignetting, corner softness are far bigger issues with rangefinder type cameras than they were with reflex cameras. MUCH more an issue with compact cameras too even with good quality lenses (35mm era again lens very close to film plane)

One reason we probably have not seen an UWA lens from Sony...it's going to be difficult to get good peripheral performance even with the new micro lenses.
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AFairley
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« Reply #24 on: October 18, 2013, 01:06:00 PM »
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The lens adapter issue is ridiculously overblown.  In the real world, you are using liveview with adapted lenses and manual focus.  Unless the adapter has hideous slop in its proportions, you'll be able to get very high quality results.
+1, in his blog, Cicala points out that the graphs are measured on an optical bench, not acutal camera/lens combos and the graphs look much more alarming that real life results.
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BJL
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« Reply #25 on: October 18, 2013, 01:55:35 PM »
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A native mount lens will make the rear elements sit very close to the sensor. ... Vignetting, corner softness are far bigger issues with rangefinder type cameras than they were with reflex cameras.
The problem with some rangefinder style lenses on digital sensors is that their exit pupil is close to the sensor, due to using near-symmetrical designs for wide angle lenses, leading to the chief ray striking the edges of the sensor at a highly off-perpendicular angle. But lens designs can have rear elements very close to the sensor while using retro-focal designs that give a high exit pupil and have good near-perpindicular incidence of light across the whole frame. And lens designs for mirrorless cameras can have the rear elements as far from the focal plane as they want, if that helps IQ.

To put it another way, the shorter registration distance of mirror-less cameras only increases options for lens designs; it does not force the use of designs with low back-focus and low-exit pupil.
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Jeff Kott
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« Reply #26 on: October 18, 2013, 04:40:22 PM »
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The lens adapter issue is ridiculously overblown.  In the real world, you are using liveview with adapted lenses and manual focus.  Unless the adapter has hideous slop in its proportions, you'll be able to get very high quality results.

+1

I've been shooting adapted M mount lenses on my Nex 7 (which has much higher pixel density than the A7r) with no problems.
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dreed
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« Reply #27 on: October 18, 2013, 10:36:50 PM »
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I've been shooting adapted M mount lenses on my Nex 7 (which has much higher pixel density than the A7r) with no problems.

But aren't you only using the center part of the image circle that the M mount lenses generate and not the edges?
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ErikKaffehr
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« Reply #28 on: October 19, 2013, 02:23:20 AM »
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Hi,

That is indeed true. On the other hand the A7 uses offset pixels, like Leica M. Michael Reichmann indicated that the A7 works well with longer M-lenses but less well with wide angles. The same problem also applies to the M series but those take care some of the problems in software.

I would suggest that there are many older lenses that can be used, Leica R and Minolta MD comes to mind.

Mechanical adapters don't influence optics, but they can affect alignment. That is not really a big problem in many cases as you often only have a central point of focus, but an excessive tilt of the lens would cause problems.

My guess is that using good adapters at moderate apertures is not a problem.

Best regards
Erik


But aren't you only using the center part of the image circle that the M mount lenses generate and not the edges?
« Last Edit: October 19, 2013, 02:28:42 AM by ErikKaffehr » Logged

Manoli
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« Reply #29 on: October 19, 2013, 04:03:33 AM »
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The same problem also applies to the M series but those take care some of the problems in software.

.. and microlens design.

Mechanical adapters don't influence optics, but they can affect alignment. That is not really a big problem in many cases as you often only have a central point of focus, but an excessive tilt of the lens would cause problems.

.. COULD cause problems - with an excessive weight hanging off the end of the adapter. Unless you support the camera/lens under the lens for hand held shooting or, preferably, a tripod mounting foot on the lens or adapter.

Bottom line: legacy lenses >= 50mm are, on the whole, more than usable with an adapter. Sony have, approximately, 15 lenses planned for the Alpha over the next 18 months - those wide angles need to be stellar.

If, on the other hand, you're thinking of buying an A7 to hang a 1kg Zeiss Otus, via an adapter, off the diminutive Alpha - then I would suggest that misalignment problems aren't the core issue you're facing ... !  [Light hearted quip - not directed at you, Erik]

On a more serious note, one thing I have yet to see any reports or comments on, is the 'adaptability' of the Alpha with tilt-shift lenses.
« Last Edit: October 19, 2013, 04:20:17 AM by Manoli » Logged
Manoli
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« Reply #30 on: October 19, 2013, 08:36:18 AM »
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I'm not sure that I understand why anyone would buy an Alpha 7, Alpha 7R if it is size & weight that you're concerned about  ...

On a more pragmatic note, and to return to the OP's original, very valid comments, an A7 compared to a Nikon 610 is less than 3/4 inch (1.7cm) smaller in width and height and weighs 474g v 760g. These differences could be as much of a hindrance as a benefit if the lenses don't offer substantial advantages. Wouldn't ditch my Nikon or Canon system just yet ..
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ErikKaffehr
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« Reply #31 on: October 19, 2013, 10:13:53 AM »
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Hi,

I don't think Nikon 610 is full frame? There are advantages to larger sensor. Also, the A7 is a mirrorless design.

Best regards
Erik

On a more pragmatic note, and to return to the OP's original, very valid comments, an A7 compared to a Nikon 610 is less than 3/4 inch (1.7cm) smaller in width and height and weighs 474g v 760g. These differences could be as much of a hindrance as a benefit if the lenses don't offer substantial advantages. Wouldn't ditch my Nikon or Canon system just yet ..
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Manoli
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« Reply #32 on: October 19, 2013, 11:06:23 AM »
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I don't think Nikon 610 is full frame? There are advantages to larger sensor. Also, the A7 is a mirrorless design.

Erik,
FYI Nikon 610 is 24MP, 24x36 full frame, the evolved version of D3x, D600. Canon parallel offerings are the 5DIII, 6D - there may be others ...
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Hening Bettermann
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« Reply #33 on: October 19, 2013, 01:04:44 PM »
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@BJL, post #25

> The problem with some rangefinder style lenses on digital sensors is that their exit pupil is close to the sensor, due to using near-symmetrical designs for wide angle lenses, leading to the chief ray striking the edges of the sensor at a highly off-perpendicular angle. But lens designs can have rear elements very close to the sensor while using retro-focal designs that give a high exit pupil and have good near-perpindicular incidence of light across the whole frame. And lens designs for mirrorless cameras can have the rear elements as far from the focal plane as they want, if that helps IQ.

To put it another way, the shorter registration distance of mirror-less cameras only increases options for lens designs; it does not force the use of designs with low back-focus and low-exit pupil.

@Erik Kaffehr, post #28
> I would suggest that there are many older lenses that can be used, Leica R and Minolta MD comes to mind.

Uff, this would mean if one wants to use existing WA lenses (not future ones, specifically designed taking advantage of the design freedom of the mirrorless house) one would be well advised to use retrofocus designs?? This will give away a large part of the weight advantage I have been looking forward to for years... :-(

Good to know though - I will then keep my 24 mm Nikkor and 28-70 mm C/Y Vario Sonnar rather than buy WA M-mount lenses...
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stevesanacore
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« Reply #34 on: October 19, 2013, 03:40:24 PM »
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In my humble opinion I think Sony are heading in the right direction here.  The EVF aspect is what appeals to me as much as anything else.  Much as I love a really good optical VF, the EVF has many advantages, not least when shooting any video, which more people are using these cameras for now.  The Panasonic GH2 is a joy to use hand-held for shooting video on the run, where the OVF on a 5D for example forces one to shoot at arms length or on a tripod.  I would love to use a full frame Canon at eye-level with an EVF.  I am sure that in the very near future almost all DSLR's will be EVF.

Jim

+1 Totally agree with you on these points Jim
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stevesanacore
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« Reply #35 on: October 19, 2013, 03:46:12 PM »
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Really excited to see how my Canon shift lenses perform on this body and if the sensor output is on par with the Nikon D800E. That would be a great solution for my architectural and landscape work.



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barryfitzgerald
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« Reply #36 on: October 20, 2013, 05:48:32 AM »
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Reading between the lines it appears the A7 does not have offset micro lenses, but the A7r does.
That being the case the A7 is going to have much worse performance at the edges and corners.

Looks like a bit of a mess up here because the A7 might turn out to be a very bad choice for people using wider angle lenses.
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Hening Bettermann
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« Reply #37 on: October 20, 2013, 06:07:01 AM »
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To the admins: This thread seems to be malplaced under 'About this site'.
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Bernard ODonovan
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« Reply #38 on: October 20, 2013, 06:34:13 AM »
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a7   - 24MP and additional PDAF

http://www.sony.net/Products/di/en-us/products/uxc2/index.html#features

a7R - 36MP, 16Bit processing, no AA filter, offset gapless microlens and additional metal body parts to support larger lenses

http://www.sony.net/Products/di/en-us/products/o4j5/index.html#features

a7 Test confirming some lenses have issues on the non r model:

http://www.ronscheffler.com/techtalk/?p=224

Feedback on that article (see Henry's comment) suggesting the r model may actually fair worse for some lenses

Best wait for more testing if you own any lenses that could be affected....

Also, the a7 has a faster Flash sync speed of 1/250 sec and selectable Electronic front curtain shutter. The a7R does not and only goes to 1/160.

a7R specs:

http://www.sony.net/Products/di/en-us/products/o4j5/index.html#specifications

a7 specs:

http://www.sony.net/Products/di/en-us/products/uxc2/index.html#specifications

« Last Edit: October 20, 2013, 09:35:24 AM by Bernard ODonovan » Logged
dreed
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« Reply #39 on: October 20, 2013, 09:58:39 AM »
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To the admins: This thread seems to be malplaced under 'About this site'.

For better or worse it seems that threads of discussion about topics presented (such as the Alpha A7R hands on preview) generally end up in this forum ... sometimes (like this), they're gear focused.
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