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50th anniversary
- Thread starter polypal
- Start date
Jürgen, no dealer in the USA has a V-mount plate. They have been on order for months and nobody can supply a delivery date. It appears that the Arca-Swiss distributor in the USA doesn't want to invest in inventory so that every order becomes a special order to the factory. This can take several months.
wbulte
Active Member
Hi Jurgen,
I know that the AOV are approximately the same. But the thing is, a Biogon is a 'classic' wide angle, so it illuminates the film (or sensor) differently from the retrofocus CF40.
Given the current discussion on "digital" lenses one would imagine that the Biogon would be at the disadvantage on a digiback.
Wilko who just finished scanning his nightshots from Berlin. I'll post some in due time.
I know that the AOV are approximately the same. But the thing is, a Biogon is a 'classic' wide angle, so it illuminates the film (or sensor) differently from the retrofocus CF40.
Given the current discussion on "digital" lenses one would imagine that the Biogon would be at the disadvantage on a digiback.
Wilko who just finished scanning his nightshots from Berlin. I'll post some in due time.
Hi Q.G.,
> The more asymmetrical a lens, the more distortion is a problem.
What type of distortion? Optics are not my strong point, and I retain little of what I've learned about them due to simple lack of use of the knowledge (and probably lack of high interest).
> The issue (if one) is not with wide angle lenses only, but with all > lenses that have the exit pupil close to the sensor.
Understood, but this does seem to manifest it self in wider angle lenses more so, doesn't it, simply by design...perhaps more so in 35mm?
From my experience, given how far away the standard Hasselblad lenses are from the focal plane (which is pretty far), I'd hazard a guess that there probably aren't going to be any problems with any of the lenses that can mount on a 50x/20xx etc. body, or the problems would be insignificant to most. Where in a rangefinder, those lenses would more likely pose a problem...because of the different design criteria.
> And with the Zeiss/Hasselblad lenses that includes a lens like the 80 > mm, while the widest of the bunch, the 30 mm F-Distagon, is not the > worst (better than the 80 mm in fact).
Interesting.
> But i don't know whether it is an issue at all with Zeiss/Hasselblad > lenses. > It wasn't reported by people using digital backs behind a Biogon, and > if any, that lens would be the one that would be worst and show it > most.
I wasn't even thinking in terms of a digiback on a Biogon! But sure, that, I would have guessed, would probably be the worst...given how shallow the body is. It really depends on the size of the sensor if a particular lense is going to be a problem. Leica decided to mitigate this (much to my consternation) by using a smaller sensor. I have an SWA, and had a full size scanning back...but never hooked the two together...never even thought of it, unfortunately. Would have been interesting.
"Microlenses" are one answer to this problem though...but in the case of the Biogon, it may be too extreme.
Regards,
Austin
> The more asymmetrical a lens, the more distortion is a problem.
What type of distortion? Optics are not my strong point, and I retain little of what I've learned about them due to simple lack of use of the knowledge (and probably lack of high interest).
> The issue (if one) is not with wide angle lenses only, but with all > lenses that have the exit pupil close to the sensor.
Understood, but this does seem to manifest it self in wider angle lenses more so, doesn't it, simply by design...perhaps more so in 35mm?
From my experience, given how far away the standard Hasselblad lenses are from the focal plane (which is pretty far), I'd hazard a guess that there probably aren't going to be any problems with any of the lenses that can mount on a 50x/20xx etc. body, or the problems would be insignificant to most. Where in a rangefinder, those lenses would more likely pose a problem...because of the different design criteria.
> And with the Zeiss/Hasselblad lenses that includes a lens like the 80 > mm, while the widest of the bunch, the 30 mm F-Distagon, is not the > worst (better than the 80 mm in fact).
Interesting.
> But i don't know whether it is an issue at all with Zeiss/Hasselblad > lenses. > It wasn't reported by people using digital backs behind a Biogon, and > if any, that lens would be the one that would be worst and show it > most.
I wasn't even thinking in terms of a digiback on a Biogon! But sure, that, I would have guessed, would probably be the worst...given how shallow the body is. It really depends on the size of the sensor if a particular lense is going to be a problem. Leica decided to mitigate this (much to my consternation) by using a smaller sensor. I have an SWA, and had a full size scanning back...but never hooked the two together...never even thought of it, unfortunately. Would have been interesting.
"Microlenses" are one answer to this problem though...but in the case of the Biogon, it may be too extreme.
Regards,
Austin
carl_sanders
Member
Hi Austin :"The lense is not a "digital" lens."
I think people refer to these lenses on the understanding there is nothing digital about them other than they have been refined for digital backs.
Marc: tried looking every where for catalogues and brochures on this Rollei X-Act 2, nothing,
not even on their website. First time I have seen one and it looks worth the purchase for the type of work we do. All the best and thanks for sharing the picture.
I think people refer to these lenses on the understanding there is nothing digital about them other than they have been refined for digital backs.
Marc: tried looking every where for catalogues and brochures on this Rollei X-Act 2, nothing,
not even on their website. First time I have seen one and it looks worth the purchase for the type of work we do. All the best and thanks for sharing the picture.
Austin,
With retrofocus designs (the ones that move the exit pupil away from the sensor), the distortion is of the "barrel" type.
The reason why the problem is not worst with wide angle lenses is because most of them already are of a retrofocus design.
To give an indication, the exit pupil distances of some Zeiss/Hasselblad shuttered lenses are:
30 mm: 103.9 mm
38 mm: 40.3 mm (!)
40 mm: 90.8 mm
40 mm FLE: 95.5 mm
40 mm IF: 110 mm
50 mm: 91.4 mm
50 mm FLE: 96.3 mm
60 mm: 93.9 mm
80 mm: 95.4 mm
100 mm: 115.8 mm
120 mm: 135.3
150 mm: 112.5 mm
Disregarding the exit pupil diameter, assuming all rays come from the center of the pupil, it should not be too difficult to calculate the angle of incidence at any size sensor's edge.
Except for the 38 mm Biogon, all rather far removed from the film plane already. The C version of the 40 mm lens would next worst, but still quite a difference between it and the Biogon.
By the way: the focal length or angle of view does not matter: even a short lens with a 180 degree angle of view has to project the image on that same limited size frame, sitting a good distance away from the exit pupil.
The Biogon howeversits rather close to the film/sensor. Though the angles of view of it and a 40 mm lens are very close, the difference in 'angle of projection'/angle of incidence is rather large. But a 80 mm lens, with half the angle of view of that of a 40 mm lens, is rather similar to the 40 mm lens in terms of angle of incidence.
And another by the way: these figures also 'predict' the degree of mirror vignetting you can expect with these lenses.
It's perhaps interesting to note that here too focal length itself is not the all deciding factor: the 150 mm lens does in fact better (because the pupil is closer to the mirror) than the shorter 100 mm and 120 mm lenses.
With retrofocus designs (the ones that move the exit pupil away from the sensor), the distortion is of the "barrel" type.
The reason why the problem is not worst with wide angle lenses is because most of them already are of a retrofocus design.
To give an indication, the exit pupil distances of some Zeiss/Hasselblad shuttered lenses are:
30 mm: 103.9 mm
38 mm: 40.3 mm (!)
40 mm: 90.8 mm
40 mm FLE: 95.5 mm
40 mm IF: 110 mm
50 mm: 91.4 mm
50 mm FLE: 96.3 mm
60 mm: 93.9 mm
80 mm: 95.4 mm
100 mm: 115.8 mm
120 mm: 135.3
150 mm: 112.5 mm
Disregarding the exit pupil diameter, assuming all rays come from the center of the pupil, it should not be too difficult to calculate the angle of incidence at any size sensor's edge.
Except for the 38 mm Biogon, all rather far removed from the film plane already. The C version of the 40 mm lens would next worst, but still quite a difference between it and the Biogon.
By the way: the focal length or angle of view does not matter: even a short lens with a 180 degree angle of view has to project the image on that same limited size frame, sitting a good distance away from the exit pupil.
The Biogon howeversits rather close to the film/sensor. Though the angles of view of it and a 40 mm lens are very close, the difference in 'angle of projection'/angle of incidence is rather large. But a 80 mm lens, with half the angle of view of that of a 40 mm lens, is rather similar to the 40 mm lens in terms of angle of incidence.
And another by the way: these figures also 'predict' the degree of mirror vignetting you can expect with these lenses.
It's perhaps interesting to note that here too focal length itself is not the all deciding factor: the 150 mm lens does in fact better (because the pupil is closer to the mirror) than the shorter 100 mm and 120 mm lenses.
Re angles of incidence and scanning backs:
When making a scanning camera (a bit over 10 years ago now, how time flies), a rather peculiar problem occurred.
Not vignetting, but strange patterns, resembling Newton rings, appeared in the images.
These were caused by an oily film on the sensor, with the effect changing gradually when light was hitting it at different angles while the scan bar moved up (or down) through the projected image.
A good wipe of the sensor removed the film, and the patterns.
(The thing, by the way, was extremely cheap to make - about US$ 50, and a couple of saturday afternoons - and worked perfectly well.)
When making a scanning camera (a bit over 10 years ago now, how time flies), a rather peculiar problem occurred.
Not vignetting, but strange patterns, resembling Newton rings, appeared in the images.
These were caused by an oily film on the sensor, with the effect changing gradually when light was hitting it at different angles while the scan bar moved up (or down) through the projected image.
A good wipe of the sensor removed the film, and the patterns.
(The thing, by the way, was extremely cheap to make - about US$ 50, and a couple of saturday afternoons - and worked perfectly well.)
Hi Q.G.,
> To give an indication, the exit pupil distances of some > Zeiss/Hasselblad shuttered lenses are:
> 120 mm: 135.3 > 150 mm: 112.5 mm
> the 120 mm lens does in fact better > (because the pupil is closer to the mirror) than the longer 150 mm > lens.
Seems something is wrong with the above? This one stuck out at me, so it's easy to comment on now. I'll get to the rest of the post in the AM, thanks!
Regards,
Austin
> To give an indication, the exit pupil distances of some > Zeiss/Hasselblad shuttered lenses are:
> 120 mm: 135.3 > 150 mm: 112.5 mm
> the 120 mm lens does in fact better > (because the pupil is closer to the mirror) than the longer 150 mm > lens.
Seems something is wrong with the above? This one stuck out at me, so it's easy to comment on now. I'll get to the rest of the post in the AM, thanks!
Regards,
Austin
CONGRATULATIONS !
Congratulations to all of you.
This is the best thread ever developed. Anywhere.
It reminds a lot how I felt 25 years ago, everytime I got the last issue of Petersen's Photographic. I was not really a rookie then, but sure it did help me figure it out a lot of things. I think it was the right photo magazine at the right time.
Eduardo
Congratulations to all of you.
This is the best thread ever developed. Anywhere.
It reminds a lot how I felt 25 years ago, everytime I got the last issue of Petersen's Photographic. I was not really a rookie then, but sure it did help me figure it out a lot of things. I think it was the right photo magazine at the right time.
Eduardo
What "digital lenses" are you guys talking about?
With the 35mm type DSLRs, it is "popular language" indicating usage for the smaller sensor digital cameras with a 1.5X or 1.6X factor. This was done to restore the wide field-of-views lost to the X crop factor with conventional 35mm lenses. Since there are no smaller film size equivalents available in those camera mounts they are for specific digital cameras only. I don't recall a manufacturer specifically calling them "Digital Lenses" since they would not work on a full frame sensor DSLR. DX or some designation like that is used to clarify they are for the crop frame digital cameras.
The only MF lenses I've seen having been inferred as being "digital lenses" but not directly named as such, are the new Schnieder AF lenses for the Hy6. Leaf infers that while the current Rollie lens line up can be used, these lenses should be considered for optimal performance with digital backs on their AFi version of the Hy6. There is no information offered by them as to why. A bit of research on these Schnieder lenses may reveal the answer ... or maybe not : -)
To my knowledge, Hasselblad has not called any of their lenses "Digital" except to say that the new HC/28mm is for use on the HD cameras only since it has the same purpose as DX lenses for 35mm DSLRs ... making a wider field of view available ... therefore won't provide full coverage when using a film back. All of the other HC lenses are for both digital and film use, and everyone with a H camera knows that.
Large Format lenses have gone the route of specifically naming a line of digital lenses as such. The marketing hype for these lenses is something I take with a grain of salt, preferring instead to listen to photographers with practical experience using them. Some of the conventional LF lenses are just fine, and I have ordered new Rollie lens boards for a few of my existing "conventional" lenses that I used with film. However, some of the so called digital lenses do seem to perform better according to studio shooters doing critical table top, architecture, and automobile work. This is based on observation of the results.
Q.G. said: " But yes, whether you need an extra filter in front of the lens to do that with any of the available digital cameras is highly doubtful. Those filter are already 'built-in".
This has been an on-going debate which was brought to a head with the introduction of the Leica M8. As we know, the rear element of Rangefinder lenses sits very close to the film plane which prevented Leica from offering a digital version of the M camera (or so they insisted). The Epson RD-1 somewhat disproved that by using an existing Sony sensor with a 1.5X crop factor. Leica's solution was the use of a newer Kodak sensor employing micro-lenses to correct the light path issue at the edges especially with wider lenses. The problem arose when a thin ineffectual IR filter was employed in front of the sensor ... which in turn required IR filters on the lenses themselves.
With the 35mm type DSLRs, it is "popular language" indicating usage for the smaller sensor digital cameras with a 1.5X or 1.6X factor. This was done to restore the wide field-of-views lost to the X crop factor with conventional 35mm lenses. Since there are no smaller film size equivalents available in those camera mounts they are for specific digital cameras only. I don't recall a manufacturer specifically calling them "Digital Lenses" since they would not work on a full frame sensor DSLR. DX or some designation like that is used to clarify they are for the crop frame digital cameras.
The only MF lenses I've seen having been inferred as being "digital lenses" but not directly named as such, are the new Schnieder AF lenses for the Hy6. Leaf infers that while the current Rollie lens line up can be used, these lenses should be considered for optimal performance with digital backs on their AFi version of the Hy6. There is no information offered by them as to why. A bit of research on these Schnieder lenses may reveal the answer ... or maybe not : -)
To my knowledge, Hasselblad has not called any of their lenses "Digital" except to say that the new HC/28mm is for use on the HD cameras only since it has the same purpose as DX lenses for 35mm DSLRs ... making a wider field of view available ... therefore won't provide full coverage when using a film back. All of the other HC lenses are for both digital and film use, and everyone with a H camera knows that.
Large Format lenses have gone the route of specifically naming a line of digital lenses as such. The marketing hype for these lenses is something I take with a grain of salt, preferring instead to listen to photographers with practical experience using them. Some of the conventional LF lenses are just fine, and I have ordered new Rollie lens boards for a few of my existing "conventional" lenses that I used with film. However, some of the so called digital lenses do seem to perform better according to studio shooters doing critical table top, architecture, and automobile work. This is based on observation of the results.
Q.G. said: " But yes, whether you need an extra filter in front of the lens to do that with any of the available digital cameras is highly doubtful. Those filter are already 'built-in".
This has been an on-going debate which was brought to a head with the introduction of the Leica M8. As we know, the rear element of Rangefinder lenses sits very close to the film plane which prevented Leica from offering a digital version of the M camera (or so they insisted). The Epson RD-1 somewhat disproved that by using an existing Sony sensor with a 1.5X crop factor. Leica's solution was the use of a newer Kodak sensor employing micro-lenses to correct the light path issue at the edges especially with wider lenses. The problem arose when a thin ineffectual IR filter was employed in front of the sensor ... which in turn required IR filters on the lenses themselves.
Carl, I have a PDF of the Rollie Xact Brochure.
I tried to use the private message function here, but it doesn't seem to allow attachments.
Send me an e-mail and I'll send a return one with the PDF
fotografz@comcast.net
I tried to use the private message function here, but it doesn't seem to allow attachments.
Send me an e-mail and I'll send a return one with the PDF
fotografz@comcast.net
carl_sanders
Member
Marc! this does not look so promising, thought this was new product?
Robert White is a well known and much respected dealer in this country
offering services to the photographic industry.
Still interested in seeing the system though, thanks Carl
"Dear Carl
Thank you for the email. Sadly the Rollei X-act camera has ceased production. We still have stock fo the camera and a few accessories but are no longer able to offer the full system. If you wish I can post some details to you if you let me have your address.
Alternatively are there any other systems you are interested in?"
Jon
jon@robertwhite.co.uk
Robert White is a well known and much respected dealer in this country
offering services to the photographic industry.
Still interested in seeing the system though, thanks Carl
"Dear Carl
Thank you for the email. Sadly the Rollei X-act camera has ceased production. We still have stock fo the camera and a few accessories but are no longer able to offer the full system. If you wish I can post some details to you if you let me have your address.
Alternatively are there any other systems you are interested in?"
Jon
jon@robertwhite.co.uk
Austin,
You caught me in the minute between writing it and correcting the mix-up. It is of course, the longer 150 mm that does better than the shorter 120 mm.
Marc,
When the IF version of the Zeiss/Hasselblad 40 mm lens appeared, it was presented as being particularly suited for digital photography. Both Zeiss' and Hasselblad's websites still carry statements to that effect.
So, though not exactly calling it a 'digital lens', both Hasselblad and Zeiss took part in this too. Yet neither have said what in particular would make this lens that.
They have also, on more than one occassion, recommended the 120 mm lens as a good lens to be used for digital photography. Again, no clue offered why that would be.
You caught me in the minute between writing it and correcting the mix-up. It is of course, the longer 150 mm that does better than the shorter 120 mm.
Marc,
When the IF version of the Zeiss/Hasselblad 40 mm lens appeared, it was presented as being particularly suited for digital photography. Both Zeiss' and Hasselblad's websites still carry statements to that effect.
So, though not exactly calling it a 'digital lens', both Hasselblad and Zeiss took part in this too. Yet neither have said what in particular would make this lens that.
They have also, on more than one occassion, recommended the 120 mm lens as a good lens to be used for digital photography. Again, no clue offered why that would be.
Carl, info is on the way.
Xact ceased production is news to me. I ordered one and got it brand new in a nice carrying case. All accessories I've ordered have come in also.
O.G., could it be because of the additional corrections or specific characteristics of those lenses, especially given that digital tends to exaggerate color fringing when contrasty edges butte up to each other?
Xact ceased production is news to me. I ordered one and got it brand new in a nice carrying case. All accessories I've ordered have come in also.
O.G., could it be because of the additional corrections or specific characteristics of those lenses, especially given that digital tends to exaggerate color fringing when contrasty edges butte up to each other?
carl_sanders
Member
Mark,
Xact ceased production is news to me. I ordered one and got it brand new in a nice carrying case. All accessories I've ordered have come in also.
May be the last of present stock, Robert whites are the sole importer for Rollei UK.
this pdf is downloading as we write, thanks
Xact ceased production is news to me. I ordered one and got it brand new in a nice carrying case. All accessories I've ordered have come in also.
May be the last of present stock, Robert whites are the sole importer for Rollei UK.
this pdf is downloading as we write, thanks
Marc,
We can have a few guesses:
- They say the 40 mm lens can lay down 200 lp/mm on film that is capable of recording such high spatial frequencies.
Great for creating jaggy edges in digital images. So that's not it.
- The corner performance of this lens has been significantly improved, compared to its predecessor.
Now where are those big enough sensors that reach all the way into the corners? So that's not it either.
- The angle of view of this lens is slightly wider than that of the old 40 mm.
That could be a plus. But then: the difference will be minute.
And to confuse matter: on Zeiss' very own Lens Data Sheets the angle of view of the old version is said to be slighty larger.
So that will not be it either.
- The lens can focus a bit closer than its predecessor, allowing to frame subjects a bit tighter. Given the crop factor current sensors still lumber photographers with, perhaps not a great plus.
Yet, being able to focus closer is indeed a plus.
- The performance of the lens at close range has been inmproved over that of the older version. In particular, it will produce a flatter field.
That would indeed be a plus in digital photography.
- One thing they do not mention is that the above mentioned improvements are paid for by a doubling of distortion. Distortion is worst near the edges and in the corners, the exact same bits the too-small sensors clip away.
So maybe that is what makes this lens particularly suited for digital photography (even though it, of course, is the other way round: the too-small sensors used in digital photography are particularly suited to hide this flaw of the lens)?
We can have a few guesses:
- They say the 40 mm lens can lay down 200 lp/mm on film that is capable of recording such high spatial frequencies.
Great for creating jaggy edges in digital images. So that's not it.
- The corner performance of this lens has been significantly improved, compared to its predecessor.
Now where are those big enough sensors that reach all the way into the corners? So that's not it either.
- The angle of view of this lens is slightly wider than that of the old 40 mm.
That could be a plus. But then: the difference will be minute.
And to confuse matter: on Zeiss' very own Lens Data Sheets the angle of view of the old version is said to be slighty larger.
So that will not be it either.
- The lens can focus a bit closer than its predecessor, allowing to frame subjects a bit tighter. Given the crop factor current sensors still lumber photographers with, perhaps not a great plus.
Yet, being able to focus closer is indeed a plus.
- The performance of the lens at close range has been inmproved over that of the older version. In particular, it will produce a flatter field.
That would indeed be a plus in digital photography.
- One thing they do not mention is that the above mentioned improvements are paid for by a doubling of distortion. Distortion is worst near the edges and in the corners, the exact same bits the too-small sensors clip away.
So maybe that is what makes this lens particularly suited for digital photography (even though it, of course, is the other way round: the too-small sensors used in digital photography are particularly suited to hide this flaw of the lens)?
Hi Q.G.,
> - The performance of the lens at close range has been inmproved over > that of the older version. In particular, it will produce a flatter > field. > That would indeed be a plus in digital photography.
Would that also not be a plus for film photography as well?
Regards,
Austin
> - The performance of the lens at close range has been inmproved over > that of the older version. In particular, it will produce a flatter > field. > That would indeed be a plus in digital photography.
Would that also not be a plus for film photography as well?
Regards,
Austin