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Lenses for 35mm format covering 44x33mm
  
 
alundeb
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p.1 #1 · p.1 #1 · Lenses for 35mm format covering 44x33mm


Lenses for the 35 mm format have got a new pontetial use case with medium format mirrorless cameras. This thread started as a spin-off of this being discussed in the Fuji GFX 50S Pre-orfer thread.

Our valued member Rich has started a similar topic, but limited to Leica R lenses:
http://www.fredmiranda.com/forum/topic/1462218/0

I will start out here with some tests made with the Sony A7r and a Fotodiox shift adapter that provides 10mm of shift. When shifted vertically, this makes it possible to record up to 44x36 mm. This more than covers 44x33 mm.

All contributions and discussions related to adapting small format lenses on medium format cameras are appreciated.

At the time this thread started, the Fuji GFX had not started shipping. After some time, when it is available to adapter-minded photographers, tests with this camera will possibly be more accurate, especially regarding isuues related to angle of incidence and filter stack / microlenses.



Mar 11, 2017 at 06:04 PM
alundeb
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p.1 #2 · p.1 #2 · Lenses for 35mm format covering 44x33mm


First out will be the Zeiss Planar 50mm f/1.4 ZF.2. The image circle is large enough to cover 44x33mm, but as we will see the corners are blurred. This example may serve as a proof that the method is not cheating, and hang on, it gets better with other (longer) lenses!

A little bit about the method. I shot with the A7r horizontal, and used 10 mm vertical shift, with the area of interest in the lower part. The image was then cropped to the lower (outer) 33x22 mm, corresponding to one half of the 44x33 mm sensor, in vertical orientation. Illustration:






The distance was about 100m. Optically, this is representative of infinity, but with minimal problems with atmospheric conditions.

For a couple of lenses in this first round, I shot wide open followed by f/8. I will present the "Half-image", and crops representing the edge and corners of a 44x33mm sensor. I will also present crops corresponding to the corners of a 5:4 aspect ratio crop.
Half-image, f/1.4:






Half-image, f/8:






Edge, f/1.4:






Edge, f/8:






Left corner, f/1.4:






Left corner, f/8:






Right corner, f/1,4:






Rigth corner, f/8:






5:4 left corner, f/1.4:






5:4 left corner, f/8:






5:4 right corner, f/1.4:






5:4 right corner, f/8:









Mar 11, 2017 at 06:05 PM
alundeb
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p.1 #3 · p.1 #3 · Lenses for 35mm format covering 44x33mm


Voigtländer Nokton 58mm f/1.4 SL

Half-image, f/1.4:






Half-image, f/8:






Edge, f/1.4:






Edge, f/8:






Left corner, f/1.4:






Left corner, f/8:






Right corner, f/1,4:






Rigth corner, f/8:






5:4 left corner, f/1.4:






5:4 left corner, f/8:






5:4 right corner, f/1.4:






5:4 right corner, f/8:








Mar 11, 2017 at 07:50 PM
alundeb
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p.1 #4 · p.1 #4 · Lenses for 35mm format covering 44x33mm


Voigltänder Apo-Lanthar 90mm f/3.5 SL

Half-image, f/3.5:






Half-image, f/8:






Edge, f/3.5:






Edge, f/8:






Left corner, f/3.5:






Left corner, f/8:






Right corner, f/3.5:






Rigth corner, f/8:






5:4 left corner, f/3.5:






5:4 left corner, f/8:






5:4 right corner, f/3.5:






5:4 right corner, f/8:









Mar 11, 2017 at 08:26 PM
flash
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p.1 #5 · p.1 #5 · Lenses for 35mm format covering 44x33mm


Is changing the sensor (different cover glass and different microlenses) going to affect the edge performance? Certainly you can check image circles but ultimately performance might be totally different on the GFX camera.

Gordon



Mar 11, 2017 at 08:28 PM
alundeb
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p.1 #6 · p.1 #6 · Lenses for 35mm format covering 44x33mm


The performance may very well be different on the GFX. The A7r sensor is not the most friendly to angles.

There are certain aspects that still are intersting from what we can see here.

Of course, what is sharp here will possibly be sharp on another sensor.

What is really interesting, is lateral CA, which seems to increase considerably towards the corners. It may also be difficult to correct, as a general correction will over-correct closer to the center, and we will likely net get profiles.

This may be a show-stopper for using the "good" lenses for landscape.



Mar 11, 2017 at 08:49 PM
alundeb
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p.1 #7 · p.1 #7 · Lenses for 35mm format covering 44x33mm


Two longer lenses were tested in the first round, but unfortunately the f/8 shost were useless because of shutter vibration. Still the wide open shots are quite sharp already and as we shall see the CA will be the most obvious problem with these (vignetting aside of course).

Voigtländer Apo-Lanthar 180mm f/4.

Wide open at f/4, half-frame and left and right corners:

















Mar 12, 2017 at 03:54 PM
 

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alundeb
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p.1 #8 · p.1 #8 · Lenses for 35mm format covering 44x33mm


SMC Pentax F* 300mm f/4.5

Wide open at f/4.5, half frame and left and right corners:

















Mar 12, 2017 at 03:55 PM
Sam_W
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p.1 #9 · p.1 #9 · Lenses for 35mm format covering 44x33mm


The original A7r is quite, quite useless with any glass that has strong angles toward the sensor. This is important because taking a lens and shifting it 10mm will greatly change the angles. Basically, it's like taking an SLR lens and converting it into a rangefinder lens: you'll get terrible results from it, just like can be seen.

It would be reasonable to assume that the lenses are quite fine, but the A7r's sensor glass is ruining anything you shift on it, unless it's MF glass that already has fantastic ray angles.



Mar 12, 2017 at 08:38 PM
alundeb
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p.1 #10 · p.1 #10 · Lenses for 35mm format covering 44x33mm



Sam_W wrote:
The original A7r is quite, quite useless with any glass that has strong angles toward the sensor. This is important because taking a lens and shifting it 10mm will greatly change the angles. Basically, it's like taking an SLR lens and converting it into a rangefinder lens: you'll get terrible results from it, just like can be seen.

It would be reasonable to assume that the lenses are quite fine, but the A7r's sensor glass is ruining anything you shift on it, unless it's MF glass that already has fantastic ray angles.


I get your point but I think you exaggerate quite, quite a bit

Shifting 10 mm does not mean extending the image circle by 10 mm from center. The images you see have 6 mm extended image circle from center.

I don't think the planar 50 ZF will look just fine.

One of the problems I get with the A7r and RF lenses due to angle of incidence, is color shift. I don't see any of that at all in these images.



Mar 12, 2017 at 08:50 PM
JohnJ
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p.1 #11 · p.1 #11 · Lenses for 35mm format covering 44x33mm


There are a huge range of enlarging lenses available to you as well, typically at the longer than 60/70mm range (possibly depending on the lens design).

I'd suggest any enlarging lens designed for 6x6 and larger negs should provide excellent coverage and may be worth investigating.

Using such lenses as 'taking lenses' with a helicoid is very simple to do. Some have an interesting drawing style (read: have aberrations that can be used to advantage) whilst others may be extremely well corrected for optimum image quality, such as the APO enlarging lenses from various makers. Atypically of enlarging lenses, some have very smooth background bokeh, ie the APO-Rodagon-N 4/80, whilst many EL's have poor/harsh bokeh. Some have poor performance at infinity, others are excellent. Point is, there are a range of lenses with a range of pro's and con's (including price) that many people ignore.

A fairly extensive list of enlarging lenses with relevant specs (where known) is here: http://www.photocornucopia.com/1061.html



Mar 12, 2017 at 09:24 PM
Sam_W
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p.1 #12 · p.1 #12 · Lenses for 35mm format covering 44x33mm


alundeb wrote:
I get your point but I think you exaggerate quite, quite a bit

Shifting 10 mm does not mean extending the image circle by 10 mm from center. The images you see have 6 mm extended image circle from center.

I don't think the planar 50 ZF will look just fine.

One of the problems I get with the A7r and RF lenses due to angle of incidence, is color shift. I don't see any of that at all in these images.


Actually, the problems on the A7r are smudging more than colour shifts. Just search through the posts regarding using Leica M glass on it. Way more smudge than colour shift. You only get colour shifts from obscenely angled lenses, like the Hologon G 8/16 or Biogon 4.5/21 ZM.



Mar 12, 2017 at 09:42 PM
alundeb
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p.1 #13 · p.1 #13 · Lenses for 35mm format covering 44x33mm


Sam_W wrote:
Actually, the problems on the A7r are smudging more than colour shifts. Just search through the posts regarding using Leica M glass on it. Way more smudge than colour shift. You only get colour shifts from obscenely angled lenses, like the Hologon G 8/16 or Biogon 4.5/21 ZM.


Corner smudge with the A7r is certainly a valid concern for these results at 50 and 58mm. Hopefully there won't be long until we get more lenses tested on the GFX.

As I mentioned, we can already see that lateral CA is going to be another problem with many lenses. Even lenses that are regarded for having low CA, show disturbing amounts in the corners. All my three longish lenses that will work with passive adapters, CV90, CV180, Pentax 300 F*, that I own because of the compactness, are so bad regarding CA in the extended image circle that I have already dropped the idea of using them for landscape on the GFX.

The Zeiss Makro-Planar 100/2 should have low enough lateral CA, but I do not own that lens.



Mar 13, 2017 at 07:23 AM







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