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AFD MTFs?

BradleyGibson

New member
Does anyone know if there are any MTF charts available for the new Hy6 AFD lenses? I'd love to see one for the AFD 180/2.8, for example.

It's hard to get enough information to find out if they are worth the price premium, but I think a Rollei MTF (my understanding is these MTF charts are produced from real lenses, not the theoretical design) would tell me everything I need to know to figure out if the AFD's are worth the price premium over the previous-generation AF lenses.

Thanks in advance,
Brad
 
T

thsinar

Guest
hi Brad!

I will try to get something for you. Not sure if I will succeed, but I'll try.
Give me some time.

Best regards,
Thierry

Does anyone know if there are any MTF charts available for the new Hy6 AFD lenses? I'd love to see one for the AFD 180/2.8, for example.

It's hard to get enough information to find out if they are worth the price premium, but I think a Rollei MTF (my understanding is these MTF charts are produced from real lenses, not the theoretical design) would tell me everything I need to know to figure out if the AFD's are worth the price premium over the previous-generation AF lenses.

Thanks in advance,
Brad
 
T

thsinar

Guest
Brad,

I have just checked and found the little book that comes with each lens and which I have. I have found inside the Schneider AF 2.8/180 MTF chart.

I have made a quick copy of it with my Lumix, so sorry if the quality is as it is, but at least you can read it.

Best regards,
Thierry

hi Brad!

I will try to get something for you. Not sure if I will succeed, but I'll try.
Give me some time.

Best regards,
Thierry
 

PSon

Active member
Brad,

I have just checked and found the little book that comes with each lens and which I have. I have found inside the Schneider AF 2.8/180 MTF chart.

I have made a quick copy of it with my Lumix, so sorry if the quality is as it is, but at least you can read it.

Best regards,
Thierry
Thierry,
I believe Brad was asking for the AFD MTF charts. The chart you presented is the AF 2.8/180 version. But technically you are correct they are the same. I just want to clarify for Brad sake.

Brad,
I had both the 2.8/80 AF and AFD and there seems to be no differences. There are differences in some of the focal length between the MF versus the AF for example the MTF chart Thierry showed here (AF) of the 180 mm has less distortion than the MF (manual focus) 2.8/180 lens; both are Schneider lens. The MTF chart on the AF 2.8/50 has better resolution than the MF 2.8/50 (I am selling this one in favor of the 55 PC). But don't let only this MTF factor alone daunt you from liking the MF lens. I find that the MF lens has such amazing mechanics especially the precision of the finest focus mechanism. When I shoot I choose manual focus on the big bright medium format focusing screen to focus for composition instead. Thus, almost all of my lens are now in MF version. Thus, the two lens that are worthy in my book to be in AF is the Schneider Super Angulon HFT 2.8/50 PQS and the Schneider Tele-Xenar HFT 2.8/180 PQ. In addition, I do not believe the AFD is any difference from the AF with the exception of quality control may be even tighter. However, Rollei optics quality control has always been one of the best manufactory along with Sinar. Thus, this is one of the many positives of going with the Rollei/Hy6 systems is that the optics are reliable and were ahead of their time. Remember that not all digital optics are the lens of choice. An example of this is how Jack Flesher and Guy Mancuso (I give full name here for those that are new and do not know Jack and Guy and thus they deserve the credit here and Theirry as well for his time and effort to educate folks about Sinar system) lead the way with using older Leica M optics and how that influence folks to join them similar to the latest medium format wave right here at Get DPI forums. You can read more into their reason for going with the older Leica M lens. I find that the Rollei lens on the Hy6/Rollei 6008 reminds me much of the Leica M system.

Best Regards,
-Son

Best
 
T

thsinar

Guest
Yes I know, Son: but those don't exist yet.

And Brad said that he would take as well the "AF" ones.

And yes, I expect them to be the same, since it is the same optical design.

If somebody needs some other charts from the other existing Zeiss or Schneider AF, I can do the same, make a quick and dirty copy and post it.

Thanks Son,
Thierry

Thierry,
I believe Brad was asking for the AFD MTF charts. The chart you presented is the AF 2.8/180 version. But technically you are correct they are the same. I just want to clarify for Brad sake.

Brad,
I had both the 2.8/80 AF and AFD and there seems to be no differences. There are differences in some of the focal length between the MF versus the AF for example the MTF chart Thierry show here (AF) of the 180 mm has less distortion than the MF (manual focus) 2.8/180 lens; both are Schneider lens. The MTF chart on the AF 2.8/50 has better resolution than the MF 2.8/50 (I am selling this one in favor of the 55 PC). But don't let only this MTF factor alone daunt you from liking the MF lens. I find that the MF lens has such amazing mechanics especially the precision of the focus mechanism. Almost all of my lens are now in MF version. Thus, the two lens that are worthy in my book to be in AF is the Schneider Super Angulon HFT 2.8/50 PQS and the Schneider Tele-Xenar HFT 2.8/180 PQ. In addition, I do not believe the AFD is any difference from the AF with the exception of quality control may be even tighter. However, Rollei optics quality control has always been one of the best manufactory along with Sinar. Thus, this is one of the many positives of going with the Rollei/Hy6 systems is that the optics are reliable and were ahead of their time. Remember that not all digital optics are the lens of choice. An example of this is how Jack Flesher and Guy Mancuso (I give full name here for those that are new and do not know Jack and Guy and thus they deserve the credit here and Theirry as well for his time and effort to educate folks about Sinar system) lead the way with using older Leica M optics and how that influence folks to join them similar to the latest medium format wave right here at Get DPI forums. You can read more into their reason for going with the older Leica M lens. I find that the Rollei lens on the Hy6/Rollei 6008 reminds me much of the Leica M system.

Best Regards,
-Son

Best
 

PSon

Active member
Thierry, if I have a company myself you would be the top priority on my list to hire; your professionalism is much appreciated not only myself but all the folks who decided to go with Sinar system.

Best Regards,
-Son
 

PSon

Active member
One final comment from me:
For those that never had experienced with the Rollei lens but had great exposure and appreciation for the Leica M and some R lens, the manual focus (MF) mechanism of the Rollei lens is as great or even to a higher level.

-Son
 
T

thsinar

Guest
Thanks Son, much appreciated. I am a very demanding person, also with myself, that makes me sometimes spend so much time to get it right and perfect! But it's fun, and if it can help others the better.

Best regards,
Thierry

Thierry, if I have a company myself you would be the top priority on my list to hire; your professionalism is much appreciated not only myself but all the folks who decided to go with Sinar system.

Best Regards,
-Son
 

Stuart Richardson

Active member
Bradley -- when I was testing the Leaf AFI and Sinar Hy6, I compared my 80mm f/2.8 Tele-Xenar AF to the AFD version, and the results were absolutely identical at all apertures I tested (2.8, 5.6, 8, and 11). The only difference is that they left out the aperture ring, which I think was a very bad decision. For my money, I would prefer just to have the previous AF versions, rather than the AFD...why pay more for less? If there is any difference other than the lack of an aperture ring, I would be curious to hear it.
 

BradleyGibson

New member
Hi, guys,

Thank you for the replies.

Son, you are correct, this thread is a request for the AFD MTF's not the (AF MTF's).

Sinar has informed me that manufacturing tolerances have improved to the point where AFD lenses are guaranteed to deliver 60lp/mm (location unspecified) as opposed to 40lp/mm of the previous generation AF versions.

This is a minimum figure--typically these lenses would resolve much higher than this, so there may indeed be no practical difference in image quality. On the other hand, if the new tolerances do deliver markedly improved resolution, I would expect to be able to see a difference in the MTF curves.

So for now, I think I will look at the AF lenses rather than the AFD's (AFD's are 30-50% more expensive), but if someone does come across an AFD MTF, I would love to see it.

Thanks everyone, much appreciated.
-Brad
 

Stuart Richardson

Active member
Hey Brad,

Thanks for the information about Sinar's statement. If they indeed improve the tolerances, that is a good thing. That said, original AF lenses should be the same performance given that they are in spec. You might be better served by just testing a few AF lenses and seeing how they compare. I may just have gotten lucky, but comparing the AFD and the AF on 33mp backs, the results were identical. I don't know how many lp/mm that is, but it is a pretty good amount. Anyway, while I believe that they have made tolerances tighter, I am not so sure they weren't tight to begin with. And I know I said it already, but getting rid of the aperture ring and then charging more really gets me hot under the collar! The aperture ring allows you to see exactly what setting the lens is on all the time, and it makes it very quick and sure to place the lens on P or T priority. The trend of making cameras less and less tactile is really a bad one in my opinion, and just because you CAN set the aperture on the camera doesn't mean that you should have to. Sorry to harp on that, it is just one of my big pet peeves.
 

Graham Mitchell

New member
and just because you CAN set the aperture on the camera doesn't mean that you should have to. Sorry to harp on that, it is just one of my big pet peeves.
I can see the thinking behind it - you can't have both, or there would need to be a way for the aperture ring to move automatically when the camera is set, and that would be a bad design.
 

David Klepacki

New member
Hey Brad,

... comparing the AFD and the AF on 33mp backs, the results were identical. I don't know how many lp/mm that is, but it is a pretty good amount...
Hi Stuart,

Are you making a subjective judgement here, or did you actually measure this? I ask this because the amount of detail necessary to distinguish the performance of a 40 lp/mm lens from a 60 lp/mm lens is quite small.

A lens with resolving power of 40 lp/mm can theoretically distinguish a feature no smaller than 0.0125mm, and a lens with resolving power of 60 lp/mm can theoretically distinguish a feature no smaller than 0.0083mm.

So, to see a difference between two such lenses, you would have to be able test them with object features smaller than 0.0125mm but greater than 0.0083mm. Otherwise, if none of the image details were in this range, both lenses would appear to be identical.

I am curious about the setup you used to actually distinguish these fine details in this range. Can you elaborate on how you did this? Thanks!

If it is only a subjective judgement, the odds are that you did not have these range of fine details in your images.

David
 

BradleyGibson

New member
Stuart, David, you have hit on exactly the problem I have with the lp/mm statement.

We're being told the minimum performance guarantee. I suspect the "guarantee" holds true over the entire image circle, but to be clear that is my supposition--Sinar did not specify what region the lp/mm figure was for.

That being said, if the typical lens resolves over 100lp/mm over most of its image circle (which would not be unreasonable for glass of this caliber), then a 50% improvement in the minimum might not be noticable--and indeed this is what Stuart is reporting.

On the other hand, if the typical lens struggles to get much above the lp/mm guarantee, then the AFD lenses could represent as much as a 50% improvement in resolving power.

In practice, I am aware that the former case is usually the norm. In fact, Zeiss (Kornelius Fleischer) reported 250lp/mm resolving power back in 2001:

I get 250 lp/mm with the Zeiss Distagon on Agfaortho 25. It took me some years to develop the technique and eliminate all influence factors that usually prevent a tester from getting resolutions that high. By the way, I am not the only one who has mastered this technique. There are more Hasselblad users out there who reach 200 lp/mm and beyond.

I believe that Schneider glass should be comparable in capability.

That brings me to Stuart's suggestion of testing. Unfortunately testing these lenses is both difficult (none in my area) and potentially fruitless, since the digital back I have today (eMo 75LV) has a theoretical maximum resolution of 69lp/mm... Even the oldest glass should still be able to outresolve my sensor--so I need to move to 6x6 film, get a 6060 film back for the Hy6 (whoops, not available), and get my hands on a good Imacon FlexTight scanner, etc... There is also the time committment as well. Do the results hold true for the AFD lineup in general? Am I testing a good copy? A bad copy? You can see where this is going! :bugeyes:

Instead, I look at it this way: basically any significant increase in resolving power will show up in an MTF chart, provided the charts are created from measurements of real-world lenses (and I believe the Zeiss and Rollei charts are some of the few that do this). It doesn't really matter to me how they do it--by better manufacturing tolerances, new optical formulae, or with "lasers" :), improved resolution is something the MTF is designed to reveal--it should show up in the results. The Sinar & F&H guys know what they're doing--I have more confidence in their ability to measure performance than I do in mine. Plus, I'd rather be...(insert beer/wine/biking/eating/dancing/mountaineering/and oh yeah, making art!)

Stuart, your experience agrees with others I have spoken with in that no one seems to be able to tell the difference (at least on today's backs). Based on that, until I can get a good look at an AFD MTF, I think going with the standard AF lenses for the time being is the most pragmatic approach.

As for the aperture ring, I don't think I'm as bothered about the loss of the as you might be, partly because I suspect I'll be leaving the ring on 'A' all the time anyway (the handle grip has controls for both the shutter speed and aperture.

I had thought you were going to say the tactile feel of moving the ring was the bigger issue. I'm a bit puzzled because given that we're usually looking through the viewfinder when we take pictures, why look away to check the ring--the camera shows what aperture it's set to right in the finder. But I can understand everyone has their preferences, of course. I just ask in case I'm missing something obvious...

Son, thank you for the writeup on the MF lenses. As you know, I now have several MF lenses and love the way they handle. But because I will also be using these in the field, I may not always have two hands available--I may be in the mountains, or in a tree scouting my quarry. It will be nice to have AF at least for those lenses that offer it--I can (and will) still use MF in many situations. I was also unaware of the difference in MTF between the MF 180/2.8 and the AF 180/2.8. Thank you!

Kind regards,
Brad
 
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EH21

Member
I think Brad's right, and if so then the lenses are going to out-resolve the sensors anyhow. Just roughly calculating here....If you're getting 100 lp/mm then you've got one line pair for every 10 microns or about 1 sensor well. But a sensor well isn't going to see a line pair, but only a line so won't be able to resolve this. I think this is still true with the p45 or e75 as their well to well spacing is what 7 microns?

This is probably why Stuart you didn't see a difference, between the AFD and older 80mm lenses and why nearly all of my 12 rollei lenses appear to have approximately the same sharpness (well okay 11, shouldn't count the imagon in this one). Just seen what the sensor can do. But I guess if we eventually have smaller well sizes in future sensors it will be important.

Having said all that, there are notable differences in Macro contrast and color and bokeh between the different lenses.
 

EH21

Member
re:aperture ring

I like this - It's nice for example to know you can just count three clicks on either adjustment and get one stop. Say you look at the histogram and decide its underexposed - you can just count three clicks on the aperture (Rollei 6008 does 1/3 stop adjustments) or shutter and know you made the adjustment. You don't have to look - you know it.
 

Stuart Richardson

Active member
David -- the setup was not scientific, so I don't want to give the impression that my testing is definitive and rigorous. It was done at Calumet in New York. It was a setup with a color chart, various finely textured items and so on. It was lit by strobes, obviously with a tripod. I tested both AF and manual focus. I could not see any difference between the lenses on either the AFI or the Emotion 75...I am not saying there isn't a difference, just that I can't see it.

As for the ring, I am sure some people won't care. Brad the tactile feel of the ring is the most important thing to me. I just like setting with a ring on the lens rather than with a wheel on the body. I am used to Leica M, Leica R, Canon FD, Hasselblad, 4x5 and so on. Old habits die hard.

That said, I find the ability to look at the setting on the lens very helpful on the 6008AF because I use the waist-level finder. I am looking down that way anyway. The other thing is that the 6008AF turns off every 30 seconds or so to save battery life, so it takes a second to turn back on when you are using it. Having the aperture there immediately visibly confirmable makes it easier to just turn it on and fire. This is probably not an issue on the Hy6.
 

David Klepacki

New member
Well, this now begs the question as to why Sinar (and Leaf) decided to build these new AFD lenses. If the higher lp/mm tolerances cannot realistically be seen, and the manual aperture rings are preferred (or at best, do not matter to most), then what seems to be the point of the new AFD lenses?
 

David K

Workshop Member
I'm with Stuart (and others) in preferring the aperture ring, albeit for a different reason. On more than one occasion I have inadvertently changed the aperture with the dial below the shutter release button. And yes, I do know that you can program the soft key to lock this. Also, I'll underscore Son's comment above about the quality of the Rollei lenses. Typically when getting into a new system I buy more lenses than I intend to keep and then decide which to sell. I recently tested the 80, 90 and 110mm lenses and they are all so good that I simply can't make that decision based on image quality. Other things, yes, but image quality, nope.
 
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