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Sony A7 and RF wides: a possible solution.
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PostPosted: Sun Jan 18, 2015 12:26 am    Post subject: Reply with quote
rbelyell wrote:
i'm considering the a7s which i understand has no issues with WA or other rf lenses, so as to not bother with this whole magilla. like they say, its simpler to just choose the best tool for the job vs trying to remake a hemmer into a screwdriver. ):
tony

I'm afraid you are mis-informed. The A7s has the same issues at infinity with all these lenses. More subtle, because of the bigger pixels. I have a number of friends in other forums with the S and Leica glass. Those who think it's fine simply are not familiar with the particular issues.

cyrano wrote:


Anyone can criticise my cameras, it won't hurt their feelings, they're inanimate objects, it won't hurt my feelings either for that matter, I don't care..

This is a very good attitude, but some very nice people are not so tough-skiined.

memetph wrote:
These pictures made with the A7 and the Leitz WA are not very convincing. These lenses work certainly perfectly with a Leica body.
May I ask you why do you insist on trying to use them with an A7 as you own a M9 ?
in addition the A7r might be a better tool for landscape if you use it the proper lenses.

LOL no they are not very convincing, that's the whole problem!!

I'm not sure how well you know the short but intense history of the E mount. Within weeks of introduction in 2010 or so, there were adapters for every mount. I mean every mount you can think of. Sony had no clue this would happen. But the Nex-5 sensor cover is a bit thinner and a crop, so it works very very well with some RF wides like the ZM18 and the 28cron, to name a couple, but not as well with others like the CV 21/4.

Why do we like the RF glass? Because they are small and they are the best.


50/2 cron by unoh7, on Flickr

This is a fantastic setup, small footprint and high quality results. We begged and prayed for the Full Frame Nex. Many laughed. But it arrived and we had high hopes. By this time many of us had many RF lenses. The M9 had been holding value over 4k. So the A7 came, and it's mount flexibility was cynically touted by Sony, who had actually marred it with a thicker sensor cover, so Gerald would not see dust spots, I guess.

As you can see, the best 21mm ever made is basically unusable on the camera.

That is why I bought an M9.

Why would I adapt the A7 to work with the best glass and wonderful small lenses?

God lord, why would I not?

Here a direct link to the service:
http://kolarivision.com/thinfilterconversion.html


PostPosted: Sun Jan 18, 2015 1:29 am    Post subject: Reply with quote
uhoh7 wrote:

and the ZM18 another serious prospect, which could turn spectacular, here with a7:

2 roads by unoh7, on Flickr


Oh, more of this lens please.


PostPosted: Sun Jan 18, 2015 5:18 am    Post subject: Reply with quote
araucaria wrote:


Oh, more of this lens please.


I don't have a bunch ZM18 with A7 as it was not the best, but on M9:

L1018957 by unoh7, on Flickr


L1019146 by unoh7, on Flickr

This is very recent design, but now out of production. The SEM18 and this lens rule the roost optically today at 18mm. The M9 corrects color-shift very well if I code it as pre-asph 21/2.8. The M240 cannot correct it so well.

Here it is next to the 90 Summarit (an utterly fantastic 90)

Untitled by unoh7, on Flickr

looks like Lloyd has already done the sensor cover mod:
http://diglloyd.com/blog/2015/20150117_1818-SonyA7R.mod-lensBehavior.html


PostPosted: Sun Jan 18, 2015 6:19 am    Post subject: Reply with quote
I feel lucky as I only have one RF wide-angle which does not works very well on my NEX-5N. Smile


PostPosted: Sun Jan 18, 2015 8:28 am    Post subject: Reply with quote
With APS- C sensors the angles are different. I did not mention the NEX.
Uhoh ,
I thought that you had some good reasons to insist on using the A7 with RF WA though you own a M9 .
Your shots are not convincing regarding this issue. There are not stunning , they are not so bad either . So what?
At the end it is your gear.


PostPosted: Sun Jan 18, 2015 8:42 am    Post subject: Reply with quote
Gerald wrote:
uhoh7 wrote:

Gerald wrote:

You may not have noticed, but my camera is a full-frame,

so it is! Congrats!

what MF glass do you use on it?

I have MF lenses from 16mm to 400mm in varied brands: Sigma, Tamron, Pentax Takumar, Olympus, Fujinon, Nikon, Pentacon, Meyer and Carl Zeiss Jena. From Leica I have only the Elpro VIIb close-up lens.



uhoh7 wrote:
I'd suggest you join the new Sony forum at FM, and search for tests by Fred Miranda, which compare corners on...I think it was the 17-40.

The Canon 17-40mm lens is soft in the corners wide open. There are many image samples in the Internet showing it. If the softness in the corners is very evident in photos taken with a 21MP Canon 5d, imagine that it will be shockingly evident with a 36MP Sony A7r. In short, the problem is in the lens, not in the Sony A7r sensor.


I have the Canon 16-35L f/2.8 on work which also have horrible corners even on Canon DSLR Wink


PostPosted: Sun Jan 18, 2015 9:08 am    Post subject: Reply with quote
Lets keep the conversation civilized please.
The A7r was marketed as having no low pass filter, http://blog.sony.com/press/sony-introduces-first-full-frame-e-mount-lenses-2/
Quote:
The α7R model features a 36.4 effective megapixel 35mm Exmor® CMOS sensor – the highest resolution sensor in the history of Sony’s α line – with no optical low pass filter for added resolving power and increased image detail.


PostPosted: Sun Jan 18, 2015 9:13 am    Post subject: Reply with quote
Nordentro wrote:
Gerald wrote:
uhoh7 wrote:

Gerald wrote:

You may not have noticed, but my camera is a full-frame,

so it is! Congrats!

what MF glass do you use on it?

I have MF lenses from 16mm to 400mm in varied brands: Sigma, Tamron, Pentax Takumar, Olympus, Fujinon, Nikon, Pentacon, Meyer and Carl Zeiss Jena. From Leica I have only the Elpro VIIb close-up lens.



uhoh7 wrote:
I'd suggest you join the new Sony forum at FM, and search for tests by Fred Miranda, which compare corners on...I think it was the 17-40.

The Canon 17-40mm lens is soft in the corners wide open. There are many image samples in the Internet showing it. If the softness in the corners is very evident in photos taken with a 21MP Canon 5d, imagine that it will be shockingly evident with a 36MP Sony A7r. In short, the problem is in the lens, not in the Sony A7r sensor.


I have the Canon 16-35L f/2.8 on work which also have horrible corners even on Canon DSLR Wink

The 17-40, 16-35, & 16-35II all have less than perfect corners


PostPosted: Sun Jan 18, 2015 9:53 am    Post subject: Reply with quote
There is to much talk about sensors, just look how much better the corners of Biogon got with the fine tuned Loxia 35mm. I don`t think smearing can be fixed by the prosessor. Vignetting and color shifts, yes... but I doubt the CPU has anything to do with the smearing.



Source


PostPosted: Sun Jan 18, 2015 9:58 am    Post subject: Reply with quote
uhoh7 wrote:


I don't think the A7r lacks a AA filter, this was assumed by some, but I believe it's not the case. In any event, as the DB above shows the stack is not thinner than the plain A7---as many of us had originally hoped. Well you knew that, and you ask very good questions, which are the foundations of many of our frustrations with Sony Smile
Smile


What should we say ?


PostPosted: Sun Jan 18, 2015 10:05 am    Post subject: Reply with quote
Nordentro wrote:
There is to much talk about sensors, just look how much better the corners of Biogon got with the fine tuned Loxia 35mm. I don`t think smearing can be fixed by the prosessor. Vignetting and color shifts, yes... but I doubt the CPU has anything to do with the smearing.



Source


I think that you are right.


PostPosted: Sun Jan 18, 2015 6:37 pm    Post subject: Reply with quote
memetph wrote:
With APS- C sensors the angles are different. I did not mention the NEX.
Uhoh ,
I thought that you had some good reasons to insist on using the A7 with RF WA though you own a M9 .
Your shots are not convincing regarding this issue. There are not stunning , they are not so bad either . So what?
At the end it is your gear.

Well I did my best to answer your questions honestly, which considering your smug manners, was pretty silly.

I'm not trying to purvey "stunning" shots, just examples of good as designed lens performance with a digital sensor.

@Nordento: you may not think the processor can help smearing, and I have no personal opinion on the matter. The design team certainly did think it could and spent alot of effort in that direction, but you will need to dig up their Japanese interview and translate if you want the source for that. Sonyalpharumour had a link to it shortly after the A7 was released, including a pic of the team.

Oh wait, this will get you there:
http://www.sonyalpharumors.com/interview-with-sony-a7-a7r-developers-faster-lenses-are-in-development/


PostPosted: Sun Jan 18, 2015 8:30 pm    Post subject: Reply with quote
If your shots with the A7 are not stunning according to you, you wanted to show that there were bad or average ?


PostPosted: Mon Jan 19, 2015 12:18 am    Post subject: Reply with quote
Nordentro wrote:
There is to much talk about sensors, just look how much better the corners of Biogon got with the fine tuned Loxia 35mm. I don`t think smearing can be fixed by the prosessor. Vignetting and color shifts, yes... but I doubt the CPU has anything to do with the smearing.



Source


There are many who believe that a high-quality wide-angle lens has to be of symmetrical type. So maybe this desperate effort in trying to adapt symmetrical wide angle lenses to a Sony A7. In fact, there are two types of lenses: the good and bad. The above Biogon is an example of a symmetrical wide angle lens with poor performance in the corners. Note that we are talking about a 35mm lens, which is a relatively easy focal length to design!

Well, I do not intend to change anyone's mind, but I would like to raise a technical question related to one of the most common distortions in the minds of Leica fanboys. I mean the idea that retrofocus wide angle lenses are inferior to symmetrical ones. Indeed, the first retrofocus wide angle lenses from he 1950s really were bad, but the knowledge of the lenses designers improved a lot since then, and now we have retrofocus wide angle lens retrofocus of exceptional optical quality. It is incredible that many Leica M fanboys do not realized that the wide-angle lenses for the Leica S are all retrofocus, and the camera itself is not a rangefinder like the Leica M, but a SLR.

To be fair, Leica as a company has endeavored to follow the progress of technology, but the mentality of many M-system fanboys stopped in the '50s. A fact that goes unnoticed to many is that most wide angle lenses for the M system are not symmetrical. The front element is much more negative than the rear one, what makes those lenses a sort of a hybrid between a truly symmetrical and a retrofocus lens.


PostPosted: Mon Jan 19, 2015 12:43 am    Post subject: Reply with quote
Symmetrical wide angle lenses are superior, particularly in distortion. That's why all wide angle lenses for large format are symmetrical, either plasmats or in the Biogon/Angulon family.


PostPosted: Mon Jan 19, 2015 2:19 am    Post subject: Reply with quote
Nordentro wrote:
There is to much talk about sensors, just look how much better the corners of Biogon got with the fine tuned Loxia 35mm. I don`t think smearing can be fixed by the prosessor. Vignetting and color shifts, yes... but I doubt the CPU has anything to do with the smearing.



Source

I made a MTF digram from the PDFs from Zeiss.



PostPosted: Mon Jan 19, 2015 5:28 am    Post subject: Reply with quote
memetph wrote:
If your shots with the A7 are not stunning according to you, you wanted to show that there were bad or average ?

What is the point of this sarcastic question?

just another pathetic troll with nothing to contribute, but a need to be heard.


PostPosted: Mon Jan 19, 2015 6:42 am    Post subject: Reply with quote
Gerald wrote:
...It is incredible that many Leica M fanboys do not realized that the wide-angle lenses for the Leica S are all retrofocus, and the camera itself is not a rangefinder like the Leica M, but a SLR.
...


Did you notice that a symmetrical wideangle lens for a SLR camera would be not a very wide wideangle - or has the need to lock the mirror away?
So wideangles for the Leica S need to be from the retrofocus type!
Futhermore retrofocus type lenses are less problematic for CCD/CMOS with normal microlens and Bayer pattern configuration.

For commercial aerial photography symmetrical lens designs for examples like Topogon and Biogon type are designed at least until ~1970 - 20 years after the inroduction of the retrofocus ídea. Today for digital sensors image side telecentrity is used.


PostPosted: Mon Jan 19, 2015 11:43 am    Post subject: Reply with quote
ZoneV wrote:
Gerald wrote:
...It is incredible that many Leica M fanboys do not realized that the wide-angle lenses for the Leica S are all retrofocus, and the camera itself is not a rangefinder like the Leica M, but a SLR.
...


Did you notice that a symmetrical wideangle lens for a SLR camera would be not a very wide wideangle - or has the need to lock the mirror away?
So wideangles for the Leica S need to be from the retrofocus type!

Of course I know symmetrical wide angle lenses would be incompatible with the Leica S. But the fundamental question is: why did Leica not adopt the rangefinder principle in its most technically ambitious camera so far? My answer: because Leica knows very well that the rangefinder concept is totally obsolete, and retrofocus wide angle lenses can be designed to have as good performance as the best symmetrical lenses. Hence my points that it is a waste of time trying to adapt problematic symmetrical wide angle lensto the Sony A7, especially when we know that there are many retrofocus lenses of very good quality out there.


PostPosted: Mon Jan 19, 2015 11:49 am    Post subject: Reply with quote
calvin83 wrote:
Nordentro wrote:
There is to much talk about sensors, just look how much better the corners of Biogon got with the fine tuned Loxia 35mm. I don`t think smearing can be fixed by the prosessor. Vignetting and color shifts, yes... but I doubt the CPU has anything to do with the smearing.



Source

I made a MTF digram from the PDFs from Zeiss.



Nice job. According to the MTF curves, Biogon has better performance than Loxia. In practice it is the opposite, which shows that the MTF curves published by lens manufacturers need to be viewed with some caution.


PostPosted: Mon Jan 19, 2015 12:24 pm    Post subject: Reply with quote
Wink

Last edited by Nordentro on Wed Jan 21, 2015 9:42 pm; edited 1 time in total


PostPosted: Mon Jan 19, 2015 1:04 pm    Post subject: Reply with quote
Beautiful lens. The photo is technically perfect, at least for the displayed size. The stars in the bright lights show that a very small aperture like F16 was used. Certainly a tripod was employed, too. That is the smart way to shoot a night scenery. Any decent retrofocus lens would take this kind of picture as good as a $3,000 lens. The other way would be to use a hand held Leica 21mm F1.4 lens wide open, with a shutter speed of 1/10s and ISO 2500. The resulting photo would be less sharp due to camera shake, and visible noise and vignetting.

Last edited by Gerald on Mon Jan 19, 2015 1:39 pm; edited 1 time in total


PostPosted: Mon Jan 19, 2015 1:24 pm    Post subject: Reply with quote
iangreenhalgh1 wrote:
Symmetrical wide angle lenses are superior, particularly in distortion. That's why all wide angle lenses for large format are symmetrical, either plasmats or in the Biogon/Angulon family.

Yes, symmetrical lenses can have very low distortion. For example, the Fujinon EP enlarging lens 50mm F3.5 has distortion of only 0.03% for 10x magnification. The Zeiss Distagon 38mm F4.5 lens for Hasselblad film cameras was famous for its extremely low distortion.

Low distortion is important for architectural photography; however the digital photography brought the opportunity to correct any small residual distortion via software. If the optical distortion is less than a few percent, any side effect of the correction via software can be totally ignored.

Note: The Leica and Zeiss wide-angle lenses have distortion that amounts to more than 3%. So what?


PostPosted: Mon Jan 19, 2015 1:46 pm    Post subject: Reply with quote
Gerald wrote:

Nice job. According to the MTF curves, Biogon has better performance than Loxia. In practice it is the opposite, which shows that the MTF curves published by lens manufacturers need to be viewed with some caution.

I think this means the ZM version will works better on a Leica camera and the Loxia will work better on the A7 family. We have to take account of the sensor design and sensor stack too.


PostPosted: Mon Jan 19, 2015 2:00 pm    Post subject: Reply with quote
Retrofocus also has the benefit of having a more uniform illumination.

But then take a 28 1.4 or 24 1.4 retrofocus it will cost you 2000$.

Another thing is that the perspective rendering of simmetrical designes is just better, that's something you don't test on brickwalls or test charts.
Just compare an interior architecture shot done with a 24mm retrofocus and one with a 90mm without rise or swing on 4x5". Resolution differences beside, the perspective is more natural on the simmetrical design, and that perspective distortion is not something you can fix with 2D matrixes, it's something spatial. Then take into account the nice color rendering of simmetrical designs,etc...

At some point digital sensors will be made of thousands of little shallow pixels, and the leicas will be nice to have.

The anti leica agenda seems a little bit sterile to me, specially on a forum where people love lenses.
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