Mamiya 7 Lenses - Barrel distortion

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johnny.moped

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Always read that Mamiya 7 lenses were almost distortion free.
Did some more architectural stuff in the last time and found this not to be true. At least with my 80/4.




I know, it's not that bad, but I'm just wondering whether this is just a problem with my lens (so I don't think so).
My Plaubel 670 and my Apo Symmar 100mm are way better (and the Hasselblad 80/2.8 is even worse).
 
Hi!

I have not noticed any distortion with my 80mm lens. My 50mm on the other hand, has so much distortion I'm not even comfortable using it anymore.

Obviously the 50mm is a wide angle lens and some distortion is inevitable, but I really wasn't expecting it to be this much.

Will be curious to read what others here have experienced.
Maximilian
 
What are you using for scanning? I ask because initially with my Mamiya 645 negs I was getting a very small amount of distortion using the standard Epson V700 holder, but this disappeared when I switched to the betterscanning holders with the ANR glass inserts. I guess it was due to a slight curl in the negatives, which was eliminated by the ANR glass, rather than any true optical distortion from the lenses.
 
Barrel distortion or perspective distortion?

The 50 and 43 are biogon derived designs and have very little distortion. The 50 is supposed to have just 0.04% in the corners and I dont think it has moustache distortion either. The basically have zero distortion.

I have never noticed distortion with mine.

The 80 will likely have more than the wides, but this is not unusual in lens line-ups where the normal lenses are not used for buildings or subjects that tend to show distortion up.

Are you perhaps not referring to the usual distortion typical of all wide lenses where verticals converge if you point it upwards etc?


Maximilian said:
Hi!

I have not noticed any distortion with my 80mm lens. My 50mm on the other hand, has so much distortion I'm not even comfortable using it anymore.

Obviously the 50mm is a wide angle lens and some distortion is inevitable, but I really wasn't expecting it to be this much.

Will be curious to read what others here have experienced.
Maximilian
Click to expand...
 
Ah ok. I kind of guessed that if you were using a Mamiya 7 you took the scanning side of things seriously too, but I thought it was worth mentioning just in case.

I am thinking about upgrading to a 7II system at the moment too and barrel distortion is one of the things I really hoped to avoid, even if it is minor like in your example. Anyone noticed anything similar with the 65mm? This would likely be my primary lens with the 7 system.
 
I am also using the BetterScanning holders with ANR glass.

Turtle: I am actually not sure of the name of distortion (English is not my native language), but yes, the normal distortion when corners are tilted inwards. But it does seem to do this rather much for being a not so very extreme wide angle. No? My old 24mm leica on small format film (which should be even wider equivalent) distorts noticeably less.

Here is an example.

fyr.jpg


This is obviously my fault for placing a straight object in the side of a wide angle image, but still I did not know it was going to distort the lighthouse this much! I have only used this lens for about a week, but I got many surprises when I developed the film. Not many keepers.

Am I overreacting? Perhaps I should get the 65mm lens instead... Sorry for the thread drift by the way.

Maximilian
 
I see no lens distortion, but plenty of perspective distortion. It looks like you still have to learn the viewfinder - there is no consistent barrel distortion in any of the images, and I am more inclined to believe that the roof edge isn't perfectly straight than that all other horizontal lines are bent by just that amount of pincushion shape to compensate a barrel distortion of the lens.

In my experience, viewfinders/rangefinders distort more than any lens, especially as long as you haven't found the perfect eye point - tangentially aligning a roof to the finder edge or brightline can have rather unexpected and undesired results on film if you are unaccustomed to the quirks of the finder and the parallax between finder and lens. It really helps to do a few outings with a tripod and level to get a feel for the finder in a straight reference environment.
 
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Maximillian,

Thats perspective distortion and is common to all wide lenses, even those without distortion. All lenses obey this law of physics and none are better or worse than others. its therefore not related to teh Mamiya 50mm specifically.

The 50mm on the 6x7 format is actually wider for the application you used. because the frame is deeper (top to bottom) when used in the landscape format, you are effectively pointing the camera up more than you could with a 35mm camera and 24mm lens.

Think about it. 24mm is the same as the 24mm depth of a 35mm camera frame. A 50mm lens is wider than the 56mm depth of a Mamiya 7 frame and so this means you can tilt the camera up more while keeping it in the deeper frame. In this regard the 50mm on 6x7 provides the same top to bottom view as a 21mm on 35mm.
 
No, I haven't noticed any obvious barrel distorition from the Mamiya 43, 80 or 150 lenses. Having said that, I tend not to be architectural and unless you get the camera exactly level the other effects tend to swamp it anyway for the wide angles.

Great system. Give it a bit more time and practice. I did some tripod tests of the M7 with ektar 100 against my old 1Ds3 with Zeiss ZF2/35 and in big prints my wife clearly preferred the mamiya output.

Mike
 
Turtle said:
Maximillian,

Thats perspective distortion and is common to all wide lenses, even those without distortion. All lenses obey this law of physics and none are better or worse than others. its therefore not related to teh Mamiya 50mm specifically.

The 50mm on the 6x7 format is actually wider for the application you used. because the frame is deeper (top to bottom) when used in the landscape format, you are effectively pointing the camera up more than you could with a 35mm camera and 24mm lens.

Think about it. 24mm is the same as the 24mm depth of a 35mm camera frame. A 50mm lens is wider than the 56mm depth of a Mamiya 7 frame and so this means you can tilt the camera up more while keeping it in the deeper frame. In this regard the 50mm on 6x7 provides the same top to bottom view as a 21mm on 35mm.
Click to expand...
Thanks for the reply! That does make sense. Guess I'll just have to be more careful in the future when using this lens.

Maximilian
 
Maximilian said:
Thanks for the reply! That does make sense. Guess I'll just have to be more careful in the future when using this lens.

Maximilian
Click to expand...

Thats it! Its just a wide lens with a deep format (in landscape mode) and so you can angle the camera up quite a lot. its this angling up that causes the verticals to converge and in this case the tower on the right to lean in towards the centre of the frame. now if you were shooting in the portrait format, a 24mm on 35mm would allow fractionally more upward angling and so you could create more 'leaning' towers!

Stand half way up a tall building and shoot a cityscape with you 50mm and you will be astonished at how straight everything is, assuming you keep the camera nice and horizontal. Unlike some lenses, it wont turn the buildings into bananas curving inwards!
 
johnny.moped said:
Yeah, also thought about that.
But have a look on the bottom of the "wall".
As this is/was a flat building the line should be perfectly straight.
Click to expand...

If, and only if, the ground is perfectly level - it rarely is, and in this image, there seems to be a slight incline to the right. The edge of the ramp (which is constructed and can be assumed to be level) is straight, so the lens is not distorting to a visible degree.
 
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