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Comparison of MF lenses
- Thread starter jerome_m
- Start date
Kolor-Pikker
Member
This is a subject I was interested in too before jumping into MF, but didn't find anything suitable, it seems that these camera systems are just uncommon enough not to receive standardized testing. Sometimes you'll find the occasional review by someone who also has another system or DSLR, or a test by a dealer, but nothing where you can cycle though comprehensive data sets of lenses at different apertures and focal lengths.
Since testing has to be done under unchanging conditions, it would have to be performed by an entity that has ready access to all these systems, something that not many dealerships can do, let alone independent users.
Since testing has to be done under unchanging conditions, it would have to be performed by an entity that has ready access to all these systems, something that not many dealerships can do, let alone independent users.
Last edited:
jerome_m
Member
Indeed it is old.
Since "standardized testing" web sites are not to be found, anyone is aware of a site showing comparison images? For example, the same pictures taken with the Pentax 25mm, PhaseOne and Schneider 28mm and HCD28 would be interesting.
darr
Well-known member
Maybe threads should be created for the most requested lens examples (i.e., SK 28xl images, Pentax 25mm images, HCD28 images, etc.).
I think most dealers do not have a large stock of lenses sitting on their shelves (maybe B&H) or the initiative to do such tests for sale purposes (the less desirable lenses may become doorstops), so this would leave it to owners/users.
Kind regards,
Darr
I think most dealers do not have a large stock of lenses sitting on their shelves (maybe B&H) or the initiative to do such tests for sale purposes (the less desirable lenses may become doorstops), so this would leave it to owners/users.
Kind regards,
Darr
ErikKaffehr
Well-known member
Hi,
All those companies except Pentax publish MTF curves. When Leica published their curves, they were calculated and not measured.
Leica, Hasselblad and Zeiss use 10/20/40 lp/mm. Leica usually adds 5 lp/mm, too.
Rodenstock and Schneider use different schemes, it is often 15/30/60 lp/mm.
There are some problems with those curves:
1) They usually are calculated at infinity
2) They apply to flat field
3) They don't show out of focus rendition
On the plus side, they are good indication of lens performance under the conditions they are applicable for.
As an example, many lenses have significant field curvature. Field curvature may often work in our favour. Foreground is often peripheral, so a field that curves towards the photographer may bring foreground detail in focus although the camera is focused near infinity.
That also mean that sharpness is lost at the edge.
Your tests with landscape shots covering the diagonal should match MTF curves pretty well.
Best regards
Erik
All those companies except Pentax publish MTF curves. When Leica published their curves, they were calculated and not measured.
Leica, Hasselblad and Zeiss use 10/20/40 lp/mm. Leica usually adds 5 lp/mm, too.
Rodenstock and Schneider use different schemes, it is often 15/30/60 lp/mm.
There are some problems with those curves:
1) They usually are calculated at infinity
2) They apply to flat field
3) They don't show out of focus rendition
On the plus side, they are good indication of lens performance under the conditions they are applicable for.
As an example, many lenses have significant field curvature. Field curvature may often work in our favour. Foreground is often peripheral, so a field that curves towards the photographer may bring foreground detail in focus although the camera is focused near infinity.
That also mean that sharpness is lost at the edge.
Your tests with landscape shots covering the diagonal should match MTF curves pretty well.
Best regards
Erik
jerome_m
Member
For HC lenses, there is hasselbladdigitalforum.com, but it does not offer comparisons with other brands.
Quite on the contrary, many dealers have a full or almost full collection of lenses for rental.
jerome_m
Member
I was not able to find MTF data for the central shutter lenses made by Schneider Kreuznach for the PhaseOne / Mamiya cameras. Rodenstock and Schneider Kreuznach only publish MTF data for their lenses designed for technical cameras and indeed traced for different values, which makes comparison difficult.
Indeed.
This is only valid for simple lens designs. Modern wide-angles often behave in the opposite manner, with maximum corner sharpness rejected beyond the focus distance chosen for the centre point.
It does, but I only did these tests for HC or HCD lenses in MF (I did some Minolta, Sony and Nikon lenses in 24x36) and no-one has ever shown any interest in doing the same tests for other brands although:
-it is a test which is comparatively very easy to set up
-it is a test which removes most potential sources of errors
-it is a test which gives results which are useful for landscape photographers.
darr
Well-known member
I disagree, as I have had to wait on delivery when a lens was ordered from a distributor/supplier because it was not sitting on a dealer shelf. This was also the case back in my 4x5 days. I found if I was looking for a Rodenstock or SK lens without a specific mount, B&H was the best supplier, if a specific mount was necessary (Alpa, Arca Swiss, etc.) call the dealers and cross your fingers. The dealers I have dealt with in the US do not sell all the brands, so what you are looking for may not be possible if you could talk a dealer into doing it. Then a few years goes by and there is a new lens line-up.
In the real world those MTF charts are just theoretical and don't address the real issue of assembly and calibration - which is abominable for the price paid for Rody's and Schneider Digitars. The biggest culprit for me is lens skewing with one side or top/bottom not in alignment with the other side. One side will focus near and the other side will focus far. Schneider corrected two of my lenses for free but it took a fairly long time and the lenses had to be sent back to Germany. You won't know this problem exists without testing the lens yourself. They are all different..... I corresponded with another forum member who had just purchased a Rody 32mm only to find out that it was horribly out of alignment. My recommendation is to test any Rody/Schneider lens for alignment..... they all have the potential for greatness as long as they are aligned and assembled properly.
Victor
Kolor-Pikker
Member
Yes and no... You can expect a smaller dealer like Digital Transitions to carry a full suit of Phase and tech lenses, but no Hass or Leica. They're willing to dig into details, but they can only compare products they have in stock.
A big retailer like B&H is worried a lot more about profit, so good luck getting them to open the box of a $5000 lens, heck they have almost no medium format glass on display except for some H lenses.
In any case, I've thought about the possibility aggregating lens data from various forum members, but it seems that even finding a sufficiently high-density test chart for printing is proving to be difficult, currently I only found a 2000 line ISO12233 vector that hardly seems suitable for 40~80mp resolutions, and Imatest seems to want you to buy their overpriced software to print and measure their targets.
ErikKaffehr
Well-known member
Hi,
All you need for Imatest is a bit of black tape. There are some options to Imatest that are using the same basic principles.
You may look at this one: http://sourceforge.net/projects/mtfmapper/
There is another commercial product around 99$ but I cannot recall the site. If I find it I will post.
Best regards
Erik
QUOTE=Kolor-Pikker;639992]Yes and no... You can expect a smaller dealer like Digital Transitions to carry a full suit of Phase and tech lenses, but no Hass or Leica. They're willing to dig into details, but they can only compare products they have in stock.
A big retailer like B&H is worried a lot more about profit, so good luck getting them to open the box of a $5000 lens, heck they have almost no medium format glass on display except for some H lenses.
In any case, I've thought about the possibility aggregating lens data from various forum members, but it seems that even finding a sufficiently high-density test chart for printing is proving to be difficult, currently I only found a 2000 line ISO12233 vector that hardly seems suitable for 40~80mp resolutions, and Imatest seems to want you to buy their overpriced software to print and measure their targets.[/QUOTE]
All you need for Imatest is a bit of black tape. There are some options to Imatest that are using the same basic principles.
You may look at this one: http://sourceforge.net/projects/mtfmapper/
There is another commercial product around 99$ but I cannot recall the site. If I find it I will post.
Best regards
Erik
QUOTE=Kolor-Pikker;639992]Yes and no... You can expect a smaller dealer like Digital Transitions to carry a full suit of Phase and tech lenses, but no Hass or Leica. They're willing to dig into details, but they can only compare products they have in stock.
A big retailer like B&H is worried a lot more about profit, so good luck getting them to open the box of a $5000 lens, heck they have almost no medium format glass on display except for some H lenses.
In any case, I've thought about the possibility aggregating lens data from various forum members, but it seems that even finding a sufficiently high-density test chart for printing is proving to be difficult, currently I only found a 2000 line ISO12233 vector that hardly seems suitable for 40~80mp resolutions, and Imatest seems to want you to buy their overpriced software to print and measure their targets.[/QUOTE]
Kolor-Pikker
Member
Now that I think about it, Lens Rentals carries just about everything under the sun, in multiple copies, and does regular testing of rented lenses to ensure that they're working as they should, so I do wonder why they don't share their findings...
Hmm... that's actually pretty clever, I may try it out sometime.
ChrisLivsey
New member
Lens Rentals http://www.lensrentals.com/rent/medium-format/
only list Pentax MF.
They do post comparisons in the blog of 35mm gear which can be fascinating.
Kolor-Pikker
Member
I could've sworn I've seen them list other camera systems... then, who does carry all the major MF brands?
darr
Well-known member
As far as rental agents goes, it is difficult in the US to rent digital backs due to insurance requirements (this has been discussed in this forum previously), and being able to find a dealer with various lenses from different manufacturers within the same focal length is far reaching. If a dealer published the differences between similar focal length lenses, it would not be prudent for future sales as only one lens may come out on top.
What would be a great project for forum members to do is contribute to threads where individual images shot with specific focal length lenses could be looked at. But as someone that has been shooting large format and medium format professionally and personally for over 30 years, all I can say is, technique can have a lot to do with the results as well as the condition of the lenses themselves. "C'est la vie."
What would be a great project for forum members to do is contribute to threads where individual images shot with specific focal length lenses could be looked at. But as someone that has been shooting large format and medium format professionally and personally for over 30 years, all I can say is, technique can have a lot to do with the results as well as the condition of the lenses themselves. "C'est la vie."
Kolor-Pikker
Member
So far this is my conclusion too, but besides technique there are other factors that narrow down the range of shooting environments, outdoors you have atmospheric effects that can do a number on your judgement. Get an 80MP back & 150mm+ lens and watch the heat distortion destroy your hopes and dreams.
Darr, is absolutely correct about technique. A too small tripod, holding a cable release wrongly, or doing a test in a windy area are all problems.
The higher the megapixels, the more issues crop up as well. Also the aperture and focal length, are factors. You need to stop down a minimum of one stop to counter curvature of field, and more if you are shifting the lens. But the higher the MP of the back the less you can stop down with standard to wide angles. Also if you miss focus the contrast as well as the sharpness is affected.
Stopping down also steps up focus shift. The red, especially, really starts coming forward, and if you are using a wide lens, say a 35mm, but are using a 80mp back, you may have less than stellar results being you really are fighting diffraction as you get to F8.5-F8.75. 60mp and lesser backs, allows use of F11.75 so the increase in depth of focus, as well as, depth of field, covers the focus shift and all is well.
My recent tests of 135mm to 210mm lenses have shown that F 11.5 to F16 is fine with these focal lengths and 80mp backs, and F22 can be spectacular with 60mp backs when couple with these focal lengths. The 90mm to 120mm gains a bout 1/2 stop over the above quoted settings, but one should test these apertures with their own backs to determine best quality setting with the long focal lengths.
Many people have been disappointed with a lens, when the problem is more with the chosen aperture, technique, etc.
I have just been shooting with my 210mm and 150mm Apo-Sironar S Rodenstocks.
As i said before, at F22, with a 40mp and a 60mp digital back, they are stellar!
And the Schneider Apo-Symmar L are quite similar in results.
The Previous series from both manufacturers are less successful with digital backs, so look for S Rodenstocks, or L Schneiders.
If anyone wishes to discuss this further contact me, and I will be happy to talk about it.
Rod
The higher the megapixels, the more issues crop up as well. Also the aperture and focal length, are factors. You need to stop down a minimum of one stop to counter curvature of field, and more if you are shifting the lens. But the higher the MP of the back the less you can stop down with standard to wide angles. Also if you miss focus the contrast as well as the sharpness is affected.
Stopping down also steps up focus shift. The red, especially, really starts coming forward, and if you are using a wide lens, say a 35mm, but are using a 80mp back, you may have less than stellar results being you really are fighting diffraction as you get to F8.5-F8.75. 60mp and lesser backs, allows use of F11.75 so the increase in depth of focus, as well as, depth of field, covers the focus shift and all is well.
My recent tests of 135mm to 210mm lenses have shown that F 11.5 to F16 is fine with these focal lengths and 80mp backs, and F22 can be spectacular with 60mp backs when couple with these focal lengths. The 90mm to 120mm gains a bout 1/2 stop over the above quoted settings, but one should test these apertures with their own backs to determine best quality setting with the long focal lengths.
Many people have been disappointed with a lens, when the problem is more with the chosen aperture, technique, etc.
I have just been shooting with my 210mm and 150mm Apo-Sironar S Rodenstocks.
As i said before, at F22, with a 40mp and a 60mp digital back, they are stellar!
And the Schneider Apo-Symmar L are quite similar in results.
The Previous series from both manufacturers are less successful with digital backs, so look for S Rodenstocks, or L Schneiders.
If anyone wishes to discuss this further contact me, and I will be happy to talk about it.
Rod