Why do adapted lenses work so well with the A7 series?

[mark_stephan2]

<p>Why do adapted lenses work so well with mirror less bodies such as the Sony A7? Would I get similar results using my MD Rokkors with my A77 or do the A mount adapters degrade image quality thus making it a bad idea? I'm selling off some of my film gear and I'd like to hang onto my best manual focus lenses with the idea that I can use them digitally in the future.</p>

[SCL]

<p>The only mirrorless I've used is the Oly E-PL2, but I've used it with most of my old film camera lenses (RF & SLR) from the 1950s-early 2000s. I've periodically tested many against their equivalents by other manufacturers, and generally found most of them to do a fine job....perhaps because I rarely use ultra wides so retrofocus issues on the sensor lenses don't come into play, and the crop factor of sensor size significantly reduces edge distortion which might be more prominent in full frame sensors. If you already have a mirorless and only keep your best performers...you really need to test them out at your normal shooting apertures as well as wide open. Some lenses work great on one type sensor and suck on another, at least if you believe what some people report. Having said this, I just don't often get rid of any of my older lenses at this juncture - resulting in a number of m4/3 adapters covering Nikon, Leica M & LTM, Minolta, Pentax (not K), Canon FD, and Olympus OM. I suppose someday I'll cull the herd, but I'm not there yet...too busy selling off camera bodies which have accumulated but aren't getting much use.</p>

[Jochen_S]

<p>I haven't tested them. - But to me it looks as if they'd include a glass element, while the MILC adapters don't, So I'd get an A7 if I wanted MD lenses to shine on digital. - I have no clue how well they are performing though. Not even everything Leica R works as great as expected on A7 (according to reviews).</p>

[mukul_dube]

<p>Mark, all adapted lenses do not work well on the A7 series. Wide angle Leica range-finder mount lenses do not do particularly well. Lenses made for SLR mounts do much better owing, I think, to the greater distance between lens flange and sensor. As Jochen says, adapters which include glass are to be avoided.</p>

[howardstanbury]

<p>If you have an Alpha 77 that is A-mount and old MD/MC/SR-mount lenses only work across the full focus range (including infinity) with an optical adapter, and these often degrade image quality. They are also relatively rare. I wouldn't bother with that, frankly.</p>

<p>The A7 however is part of the E-mount system, has a much shorter flange-to-sensor distance, so a lot of older lenses can be used successfully by having a simple metal extension tube to make the correction.</p>

<p>An adapter for Rokkor lenses to E-mount is relatively cheap (often less than £20/$30) and the beauty of the A7 is that the full frame sensor takes the lenses as they were designed (50mm is 50mm, and so on). The A77 has an APS-C crop sensor and if you did find an optical adapter for Rokkors, the effective focal length is more like 85mm (1.5x for the crop + 10% or so for the optical correction).</p>

 

[harold_gough]

<p><img src="http://www.fredmiranda.com/forum/ufiles/04/1268604.jpg" alt="" width="1024" height="759" />They just do. A7R with Printing Nikkor 150mm f11, Nissin Flash.</p>

<p> </p>

[andylynn]

An A7 is great for adapter lenses because it has the same size frame as 35mm film (meaning the lenses are used for the

same types of shots as they were originally used for) and the flange distance is very short. Flange distance is the space

between the sensor (or film) and the lens mount. A short flange distance means there is space for the adapter to go, while

maintaining the distance between the lens and sensor that the lens was designed for. An A mount camera has a longer

flange distance than MD mount, so an MD to A adapter must have a glass element that compensates (and degrades

image quality) or else it will function as an extension tube, making it impossible to focus at long distances.

[harold_gough]

<p>To state "a glass element that compensates (and degrades image quality" is a typical, prejudiced remark found across forums. So, are all your lenses single element?</p>

[harold_gough]

<p><img src="http://www.fredmiranda.com/forum/ufiles/25/1274525.jpg" alt="" width="534" height="800" /><img src="http://www.fredmiranda.com/forum/ufiles/07/1274107.jpg" alt="" width="1024" height="1256" /><br /> <br>

Above are shots with a reversed Schneider HM 40mm lens on an A7R body, with and without a x2 TC behind it:</p>

[rdm]

Andy L wrote " . . . . An A mount camera has a longer flange distance than MD mount, . . ."

 

That is incorrect . The A mount is shorter than the MD/MC/MD mount, by 0.5mm .

That is not sufficient room to make an adapter, therefore any adapter causes the increase in focal distance. That is the reason for the increase in distance and why a corrective lens element is required, like everyone has explained.

[harold_gough]

<p>The following is a new lens, with amazing characteristics, which need an adapter for Sony E, m4/3,etc<br>

It is the Laowa 15mm shift macro. My initial shots, with background to show the effects rather than to be pretty. At f22, with twin TTL (Nissin Air) flash. The lighting is problematic due to the greatly reduced WD at higher magnifications.<br>

Sony Alpha A7R, Manual Mode, ISO 400 with twin TTL Nissin Air flash (RC) Laowa 15mm macro at f22, (The aperture ring setting is easily moved accidentally).</p>

<p><img src="http://www.fredmiranda.com/forum/ufiles/99/1290599.jpg" alt="" width="1024" height="749" /></p>

<p><img src="http://www.fredmiranda.com/forum/ufiles/00/1290600.jpg" alt="" width="1024" height="711" /><br>

<img src="http://www.fredmiranda.com/forum/ufiles/01/1290601.jpg" alt="" width="1024" height="683" /></p>