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Author Topic: An interesting publication: Lens Comparison Test-Hasselblad vs. Mamiya  (Read 18769 times)
David Schneider
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« Reply #20 on: September 01, 2011, 04:30:48 PM »
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I use my Hasselblad HC 100 more than my HC 150, but I absolutely love the 150 more. 
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Guy Mancuso
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« Reply #21 on: September 01, 2011, 08:41:14 PM »
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I heve been through the Leica factory in Solms and they do put lenses through a projector and test them. must have some relevance to this. Frankly I am not surprised at all on the LS lenses and the 150 D regardless if  they are better or worse than Hassy is meaningless but I shoot these lenses and they are stellar. Not sure about this particular test but not surprised for a second the author thinks they are good. I do . LOL
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« Reply #22 on: September 02, 2011, 09:39:42 AM »
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Guy,
I would think in a production environment, a quick test is all that's needed to know if a lens is meeting the standard like the rest or not and such a projector would be a good visual tool.  That's a lot different than comparing several lenses from different makers in different focal lengths, at varied aperture and focal distance settings.   We are just saying you can't conclude anything about the lenses other than wide open at infinity.  They may behave much differently stopped down some or focused up close eg - studio settings.  Also while both might be sharp, one might have nice bokeh and color.

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Guy Mancuso
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« Reply #23 on: September 02, 2011, 10:47:01 AM »
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I agree just found it very interesting when we walked into that area and where projecting the lens looking for certain things in the projection. Technically i have no idea what they where looking for or not, just that i have seen it in the factory and obviously has some bearing on deliver of that lens. Certainly not how I would be testing a lens on its own or against another one. I would go shoot the darn thing at most likely its working aperture. But I'm a hands on tester and don't buy much into some of these tests like DXO I still don't get it as who cares what the raw data says its the processed data in my mind is what I am going to deliver. But hey that is another can of worms and I am not getting into that can either. I care about what my final results end of story for me.
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BillOConnor
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« Reply #24 on: September 02, 2011, 11:14:35 AM »
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I couldn't agree more. Even a revered lenses like the Zeiss 85mm f1.4 is a whole different lens at f2. You buy an f1.4 lens so you CAN shoot sharp at f2.
For medium format, no lens is made to be used wide open, that aperture is for focusing.

Please.
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TH_Alpa
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« Reply #25 on: September 02, 2011, 11:21:39 AM »
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Guy,

The projector used to test the lens is a very powerful light projector, usually even cooled down with water. The lens is fixed at the front of it, absolutely parallel to projection wall. There is a translucent test chart placed in-between the light source and the lens to be tested. This lens chart is a normal resolution chart with pairs of lines of different sizes and in different directions (tangential and sagittal). The light is projected on the chart, then through the lens and finally captured on a white wall where one can check the resolution of this lens, in the image center to the edge of the IC, in both directions, tangential and sagittal. The smallest pair of lines which can be resolved (seen with the human eyes as 2 separate black lines) is giving the resolution.

Thierry

I agree just found it very interesting when we walked into that area and where projecting the lens looking for certain things in the projection. Technically i have no idea what they where looking for or not, just that i have seen it in the factory and obviously has some bearing on deliver of that lens. Certainly not how I would be testing a lens on its own or against another one
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Guy Mancuso
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« Reply #26 on: September 02, 2011, 01:38:13 PM »
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Guy,

The projector used to test the lens is a very powerful light projector, usually even cooled down with water. The lens is fixed at the front of it, absolutely parallel to projection wall. There is a translucent test chart placed in-between the light source and the lens to be tested. This lens chart is a normal resolution chart with pairs of lines of different sizes and in different directions (tangential and sagittal). The light is projected on the chart, then through the lens and finally captured on a white wall where one can check the resolution of this lens, in the image center to the edge of the IC, in both directions, tangential and sagittal. The smallest pair of lines which can be resolved (seen with the human eyes as 2 separate black lines) is giving the resolution.

Thierry


Thanks Thierry that is what it was looking like was testing with a lens resolution chart. I thought it was a interesting way to see what the lens was doing. I guess checking alignment and lens resolution of each lens before shipping , it was close to the end of the production line. I thought it was a pretty cool device.
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ErikKaffehr
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« Reply #27 on: September 02, 2011, 02:29:30 PM »
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Hi,

Lenses tend to be pretty similar once they are becoming diffraction limited...

Best regards
Erik

I couldn't agree more. Even a revered lenses like the Zeiss 85mm f1.4 is a whole different lens at f2. You buy an f1.4 lens so you CAN shoot sharp at f2.
For medium format, no lens is made to be used wide open, that aperture is for focusing.

Please.
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Quentin
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« Reply #28 on: September 02, 2011, 05:04:04 PM »
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Well that's 5 minutes of my life I can never get back  Cool.  Possibly the most useless test I have ever read - lenses not used as intended and without software corrections Hasselblad have designed in to keep down weight.    I also assume the Hassy 50mm is the old version, not the new one, which is a complete redesign. 

« Last Edit: September 02, 2011, 05:07:28 PM by Quentin » Logged

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yaya
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« Reply #29 on: September 03, 2011, 01:15:43 AM »
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Just as a side note (or two):

Lens corrections do not increase resolution or sharpness

When the HC150, 80 and 50 were introduced there were no lens corrections available for them (in ANY software) so to say that they were designed with that in mind is a bit misleading

Back to Saturday's programme Wink
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« Reply #30 on: September 05, 2011, 04:57:10 PM »
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Just as a side note (or two):

Lens corrections do not increase resolution or sharpness

When the HC150, 80 and 50 were introduced there were no lens corrections available for them (in ANY software) so to say that they were designed with that in mind is a bit misleading

Back to Saturday's programme Wink

+1
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JV
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« Reply #31 on: September 05, 2011, 05:05:08 PM »
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When the HC150, 80 and 50 were introduced there were no lens corrections available for them (in ANY software) so to say that they were designed with that in mind is a bit misleading

Obviously true, it does make me question though what software like Capture One and Phocus exactly add when they say they perform lens corrections...
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« Reply #32 on: September 05, 2011, 05:21:03 PM »
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if we test the lens, it should evaluate its optical properties. This gives us a picture of what equipment we have. Secondly, this will allow for thorough assessment and make any comparison. In this way we can compare each lens: Mamiya, Leica, Hasselblad, Nikon, Canon, Zeiss. Of course I agree that the software corrections are good and help improve the image quality. But let us not be mad, we can not speak in such a case, the lens is better because the manufacturer has a better digital correction. In this case we can talk about comparing entire systems, rather than optical element which is the lens. It's two cents from my side.
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ErikKaffehr
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« Reply #33 on: September 05, 2011, 06:40:31 PM »
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Hi,

"Digital corrections" essentially eliminate distortion and lateral chromatic aberration. The latter would influence sharpness but the digital correction itself will induce some loss of resolution as it uses interpolation to remap pixels.

A lens that is well corrected at full aperture normally also works well stopped down and most lenses will become diffraction limited somewhere about f/8. A better corrected lens becomes diffraction limited at a larger aperture.

The test indicates that the tested Mamiya lenses are on par with Hasselblad HC lenses. There are very few comparable MTF tests published on Mamiya and Hasselblad lenses. Old "Photodo" published tests of some Mamiya lenses. Those tests were done at the Hasselblad factory, by the same guy who leads the lens designs of the HC lenses. At that time the Mamiya lenses were noticeably better then the Zeiss lenses for the classic blads. The rangefinder lenses were even better.

Present HC lenses seem to have better MTF data than the old Zeiss lenses. Another difference is that the HC lenses are designed to keep sharpness at closer distances compared to the Zeiss lenses. Some lenses are better than others. Interestingly "Diglloyd" tested the HC 100mm f/2.2 and found it to have a nice bokeh for portrait work but lacking in edge sharpness for landscape work. His test is here: http://diglloyd.com/prem/prot/DAP/HasselbladH4D/examples-100mm.html

Now, we need to keep in mind that there are sample variations. Lens designers use MTF a lot, but only a subsample of MTF data is published, the ones for correct focus at infinity. At closer range some parts of the image will normally be out of focus and the drawing of out of focus images becomes important. Highly corrected lenses may have different and less pleasant bokeh than less well corrected lenses.

Best regards
Erik




if we test the lens, it should evaluate its optical properties. This gives us a picture of what equipment we have. Secondly, this will allow for thorough assessment and make any comparison. In this way we can compare each lens: Mamiya, Leica, Hasselblad, Nikon, Canon, Zeiss. Of course I agree that the software corrections are good and help improve the image quality. But let us not be mad, we can not speak in such a case, the lens is better because the manufacturer has a better digital correction. In this case we can talk about comparing entire systems, rather than optical element which is the lens. It's two cents from my side.
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paul_jones
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« Reply #34 on: September 05, 2011, 09:49:51 PM »
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nothing wrong with an test wide open. its ok to shoot buildings or landscapes at f8 or smaller, but shoot anything that breathes - like most of advertising subjects, then you need to shoot with faster lens settings. Especially with the lame ISO ratings of these backs (except maybe the pentax or p30+), I'm finding I need to shoot at faster than f4 to even get a shot.

paul
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« Reply #35 on: September 07, 2011, 10:31:30 AM »
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You are the CEO of Hasselblad and commission a survey to find out how many of our customers also indulge in astro photography.

The result comes back to less than 1%.  You tell our lens designer to....

You see my point.

Anyway, perhaps this technical article will provide an insight...

http://www.hasselblad.co.uk/media/1663143/the_evolution_of_lenses.pdf

David
But it might come back as a large percent shooting landscape. My field is aerial, I need decent far field performance. With Canon at least it's not lens resolution that lets it down, it's the AF not always getting infinity. That and the odd effect that anything faster than about 1/1600th of a second looks to induce softer images. I can't think I would sweat to much about a real World gnats whisker of lens performance between brands. If what you are using Hassy or Mamiya is doing it for you, why worry about what someone else thinks or gets. You can bet that it's swings and roundabouts, if it looks sharper it might be at the expense of gradation or distortion, photography has always been give and take, get it at one end lose it at the other.

Kevin.

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Kevin.
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« Reply #36 on: September 07, 2011, 04:05:54 PM »
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on a slightly different note regarding the article david linked to (personally was not aware of this and found it quite interesting):

it appears that CZ lenses "always" were optimized for infinity - as opposed to i.e. HC designs.

anybody in the know knows if that optimization for infinity was credo also for (all) other MF / 35mm glass producers?

Pentax, Mamiya, Bronica, etc etc. respectively canon - FD? EF? Nikon?

just curious,

cheers,
r

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Doug Peterson
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« Reply #37 on: September 07, 2011, 07:26:03 PM »
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Obviously true, it does make me question though what software like Capture One and Phocus exactly add when they say they perform lens corrections...

Edge Sharpness in C1 does not perform a miracle. It just sharpens the edges, the middle, and the center of the frame differently. It does so through some proprietary algorithms but from my experimentation it seems to be roughly the same as progressively increasing the radius and amount of the unsharp mask being applied.

But importantly it's many many times faster to turn up a slider marked "Sharpness Falloff Correction" then to first process the image (losing all advantages of a raw workflow), open in Photoshop, duplicate the background layer several times, apply several different unsharp masks (doing it on one layer will risk really ugly ghosts of halos), and then blend them together to create a progressive amount of sharpening. Even if you did an action or script in PS it's still tons faster to do in C1 via a single slider (and you don't have to leave raw).

Plus you can copy/paste the adjustment to several hundred files shot with the same lens in literally a few seconds.

It does NOT create detail that didn't exist - nothing can do that. It DOES bring out the best in the file - and with virtually zero effort.

Forgive a bit of over-simplification: really it is a continuous change but for the purpose of simple explanation we'll say edge/middle/center

Doug Peterson (e-mail Me)
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« Reply #38 on: September 09, 2011, 02:22:00 AM »
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..to build on the information from Doug Peterson and Eric Kaffehr...

The advantage of having the digital lens corrections is to compensate for the design considerations for manufacturing limitations: a perfect lens can be designed but the real kick in the pants comes when evaluating the substantial increase in cost to produce the finished assembly, so the designers and the lens crafters and the business operations must all agree on what can be produced at a given cost that the market will bear. I do not feel it is reasonable to have a price of $16,425 for a perfect 100mm f/2.2 and I suspect neither do most readers of this forum.

Since the lens performance is known at each aperture and iteration of the focal distance (moving the lens elements), the lens corrections are able to get us to that "perfect" lens performance by way of a polynomial function (calculations that take milliseconds thanks to faster processors) ...and at a cost the market will bear.

Incidentally, Hasselblad HC lenses record the precise lens position at capture in the file metadata explicitly for this calculation.

So, to evaluate a lens alone is to perform a portion of the test suitable for comparison, it is incomplete; similar to licking the dough from the spoon when preparing a batch of cookies - it gives a sense of how the cookies may taste, but not a complete comparison to the final result.

Who wants cookies?

John
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« Reply #39 on: September 09, 2011, 11:55:11 AM »
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..to build on the information from Doug Peterson and Eric Kaffehr...

The advantage of having the digital lens corrections is to compensate for the design considerations for manufacturing limitations: a perfect lens can be designed but the real kick in the pants comes when evaluating the substantial increase in cost to produce the finished assembly, so the designers and the lens crafters and the business operations must all agree on what can be produced at a given cost that the market will bear. I do not feel it is reasonable to have a price of $16,425 for a perfect 100mm f/2.2 and I suspect neither do most readers of this forum.

Since the lens performance is known at each aperture and iteration of the focal distance (moving the lens elements), the lens corrections are able to get us to that "perfect" lens performance by way of a polynomial function (calculations that take milliseconds thanks to faster processors) ...and at a cost the market will bear.

Incidentally, Hasselblad HC lenses record the precise lens position at capture in the file metadata explicitly for this calculation.

So, to evaluate a lens alone is to perform a portion of the test suitable for comparison, it is incomplete; similar to licking the dough from the spoon when preparing a batch of cookies - it gives a sense of how the cookies may taste, but not a complete comparison to the final result.

Who wants cookies?

John


In summary, there is no method to examine the lens, at least as to compare lenses from different manufacturers today. Since there is no authoritative method. The proposal does not make sense to do any tests, because they are not in the slightest way relevant. How to investigate whether the lens has been corrected to better than the other. In addition, manufacturers continue to refine these algorithms. Because of that, even if you managed to get to the method, it is also such a test would not make sense because it would become quickly outdated. Does this make sense?
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