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What Flange? Oh that flange... No pancake lens for you!


K2Kevin
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Recently, I was watching a video about the new line of Sony Full Frame lenses.  The original intent of the video was to simply make fun of Sony products and photographers that use them, but this same video also brought up an interesting point.

 

All sony full frame camera lenses incorporate a flange/spacer at the mount of the lens (about 28.x mm). Essentially this flange distance is similar to the e-mount adapters on the market for use with other brand full frame lenses (Nikon, Cannon, etc.).

 

I don't see this as a fault, it just seems to be a necessary "solution".  The only way to get light to fill that large sensor is moving the lens further from the camera.  So we do save on size of the full frame mirrorless body, but we will always have a larger/longer lens (compared to its Nikon/Cannon counterparts) due to the need for this "adaptive" distance.

 

I didn't purchase the Sony to save space, so this is really a none issue for me. But for those who did...

 

 

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There are lens designs that use the shorter flange distance in general. Just look at most rangefinder lenses. Pancake lenses correlate to the flange distance to a certain degree. So pancake lenses would be of a shorter focal length on Sony e-mount. The Sony Sel16F28, which is actually meant for apsc, almost covers the whole ff sensor and is a pancake lens. With some modifications this lens design might inspire a real full frame version.

 

http://phinioxglade.blogspot.de/2014/04/modified-sony-e-16mm-28-for-use-on-ff-a7.html

 

Or adapt a Voigtländer 35/2.5 Color Skopar from M-mount and you almost have a pancake lens despite being adapted.

 

I do not think that pancake lenses are impossible on the sony fe-mount. They are just harder to design as they need to be of a shorter focal length on the one side and still manage to have a not too steep incident angle when shining on the sensor on the other side.

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Fault? Solution? Interesting?

 

The point is lost, well and truly lost ... with the A7 platform, thanks to this short flange distance, you can adapt and mount nearly _any_ lens you want. 

 

Native E-mount, lens designers are designing for optical performance, and ergonomics. Faster lenses are never going to be small, so 28mm of extra flange distance is not really a design factor that would be worth worrying too much about     :D

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K2kevin do you know what you are talking about? I have the sony 55 1.8 has a rear element that I am afraid of touching whenever take off the rear cover. There may be others. 

To ben does the 16 really cover most of the sensor? I know this was not a well liked lens on APSC but you peaked my interest

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I'm familiar with the youtuber whose video you refer to. It should be pointed out that the same believes in perpetual motion machines, believes himself more knowledgeable about physics than Richard Feynman, and is basically the world's foremost expert on everything, including photography (although curiously he hasn't made any of his photos public). 

 

While it's true that even a stopped watch is right twice a day, you really need to take everything that guy says with a huge grain of salt. 

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To ben does the 16 really cover most of the sensor? I know this was not a well liked lens on APSC but you peaked my interest

 

The SEL16F28 is not optimal on ff, but it seems as if a slightly longer focal length say 18-20mm with a similar design should be possible. Here you can see how soft it gets once it leaves the light circle that covers the area of the apsc sensor a little better. 

 

https://plus.google.com/photos/+PhinioxGlade/albums/6008791751874417777

 

It is important to know that the lens needs to be slightly modified in order to achieve this. A rear baffle needs to be removed. If you already have this lens it is a cheap way to get some wide angle shots if you can sacrifice 2-4 MP. 

 

It was just to illustrate that Ken Wheeler ist completely wrong in his assessment that the e-mount is flawed because of its shorter flange distance. It is exactly the other way. At the time the first SLR-cameras were release lens designers had difficulties dealing with the longer register as they were used to rangefinder cameras that even allowed massively protruding rear lens elements almost touching the film.

 

Edit: Another impressive example that short flange distances are not a detriment is the lens design of the RX1 Series. Just take a look at how close the last element sits to the sensor:

 

Bildschirmfoto-2015-10-16-um-16.49.51-70

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Thanks Ben

I actually looked at a bunch of examples using google and Flikr last night. Even though you CAN use the 16 on a full frame camera with moderate coverage I do not think I will. It seems an interesting combination but all the shots I could find are not great even in the center at reasonable apertures.

As regards the rear element it seems the OP should do some research before spreading misinformation. He could have talked about how the short flange distance is underutilized. His statements about how it cannot be used are ignorant to current lens design and adapted rangefinder lenses. The adapted rangefinder lenses have their own issues but I am not going to play the fanboy vs troll game

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K2kevin do you know what you are talking about? I have the sony 55 1.8 has a rear element that I am afraid of touching whenever take off the rear cover. There may be others.

To ben does the 16 really cover most of the sensor? I know this was not a well liked lens on APSC but you peaked my interest

I stand corrected, I should have said MOST full frame, not all. I see two or three FE lenses that don't have this.

 

Just an observation, no need to get your panties in a bunch.

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Maybe I should also state, I sold all my Nikon gear over a year ago and switched to Sony A7II, then wife "needed" to do the same and she now shots a Sony A6000.

 

So no... This was never intended to put down Sony in any way shape or form, as stated, it was an observation. An observation that was originally pointed out by a self proclaimed Sony hater/troll.

 

And I am ONLY speaking about Fullframe FE lenses.

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I stand corrected, I should have said MOST full frame, not all. I see two or three FE lenses that don't have this.

 

Just an observation, no need to get your panties in a bunch.

I am cool hunny bunny. 

It was an incorrect observation. The way the internet works these incorrect observations become facts as they are repeated. 

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Recently, I was watching a video about the new line of Sony Full Frame lenses.  The original intent of the video was to simply make fun of Sony products and photographers that use them, but this same video also brought up an interesting point.

 

All sony full frame camera lenses incorporate a flange/spacer at the mount of the lens (about 28.x mm). Essentially this flange distance is similar to the e-mount adapters on the market for use with other brand full frame lenses (Nikon, Cannon, etc.).

 

I don't see this as a fault, it just seems to be a necessary "solution".  The only way to get light to fill that large sensor is moving the lens further from the camera.  So we do save on size of the full frame mirrorless body, but we will always have a larger/longer lens (compared to its Nikon/Cannon counterparts) due to the need for this "adaptive" distance.

 

I didn't purchase the Sony to save space, so this is really a none issue for me. But for those who did...

Again...... I was using my FE 28 f2 today and I realized it has almost no clearanceto the rear element. I haven't even researched this subject andi keep finding lenses that prove your post incorrect.

Cheers

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Again...... I was using my FE 28 f2 today and I realized it has almost no clearanceto the rear element. I haven't even researched this subject andi keep finding lenses that prove your post incorrect.

Cheers

 

 

Good...  glad to hear its not always the case.  

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