Guy Mancuso
Administrator, Instructor
Love it. Lol
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Credo 50 Review coming
- Thread starter Guy Mancuso
- Start date
Guy Mancuso
Administrator, Instructor
Normally that's what I would do as a workaround for sure. I just wanted to stitch for this review so we can see how CMOS sensors handle it. Which so far looks very good.
kdphotography
Well-known member
Live view is great from the CMOS sensors, as are the nice touch screens on the IQ and Credo MFDBs. But you still can't get away from middle-aged and tired eyes on the relatively small screen on the MFDB when working on location.
Enter tethering to the Surface Pro 2 or 3 with a USB3 enabled MFDB---just like that Credo 50 that you're asking your wife (and banker) about this afternoon.
The Surface Pro is small yet powerful----and a natural extension of the IQ or Credo touchscreen. Double-tap to zoom, drag a finger, focus mask, and live view of full resolution raws with C1 Pro.
You know, Don Libby has a Surface Pro 2 he's getting ready to sell. And he's just down the road from you...
:ROTFL:
Enter tethering to the Surface Pro 2 or 3 with a USB3 enabled MFDB---just like that Credo 50 that you're asking your wife (and banker) about this afternoon.
The Surface Pro is small yet powerful----and a natural extension of the IQ or Credo touchscreen. Double-tap to zoom, drag a finger, focus mask, and live view of full resolution raws with C1 Pro.
You know, Don Libby has a Surface Pro 2 he's getting ready to sell. And he's just down the road from you...
:ROTFL:
Guy Mancuso
Administrator, Instructor
My problem is I need that attached to the tripod. I walk around far too much sometimes to hold something but yes tethered is awesome and I do like it working like that.
For a sideways panorama like this I think you would get more shift with a vertical back than horizontal, ie the image you show is made in way to make the back perform as good as it can, or if we're lucky it's the other way around and it can perform even better. Did you have time to test large shifts in both vertical and horizontal orientation?
Another observation is that the bush in the center has more saturated color than the tree to the left (and also the small bush to the left). Is that a true representation of the scene, or has the sides lost saturation?
I took a look again at Doug's library shot and it holds up quite well in this range, so I think it should work quite fine. The 32 is a bit more problematic, but still can handle quite some range. Colors are not entirely stable though in either of them making it a bit scene dependent. Most often it's a slight desaturation effect, but there can also be a small color shift. It can be very hard to see that it's happening though unless one has a reference shot to compare with in constant light. In Doug's case he had IQ260 shot in parallel, where you could see some yellows in the ceiling being the same in the IQ260 and different on the IQ250. Could me a post-processing issue though, I had not the raw files for his 40HR shot so I haven't been able to analyze them fully.
Another observation is that the bush in the center has more saturated color than the tree to the left (and also the small bush to the left). Is that a true representation of the scene, or has the sides lost saturation?
I took a look again at Doug's library shot and it holds up quite well in this range, so I think it should work quite fine. The 32 is a bit more problematic, but still can handle quite some range. Colors are not entirely stable though in either of them making it a bit scene dependent. Most often it's a slight desaturation effect, but there can also be a small color shift. It can be very hard to see that it's happening though unless one has a reference shot to compare with in constant light. In Doug's case he had IQ260 shot in parallel, where you could see some yellows in the ceiling being the same in the IQ260 and different on the IQ250. Could me a post-processing issue though, I had not the raw files for his 40HR shot so I haven't been able to analyze them fully.
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Guy Mancuso
Administrator, Instructor
The back only goes to 18mm either way on a Alpa STC. It has no rise or fall to add more shots . 3 shots and your out , I did not do a horizontal back going up and down. It would perform the same as a vertical going sideways . This image is a little hard to tell since lots of shadows but I see no loss of color saturation in another one, actually it's quite good. But the back is in vertical position going 18mm on either side of center. That's the most extreme movements I can make with a Alpa STC and I only have a 40mm. Now not sure what your meaning is in regards as to back perform as it could. Is that not what we always want anyway. I'm kind of lost on your comment.
I'll be honest I'm not going to get into all this crosstalk business at all. The files will be available for folks to try and process themselves. My sole purpose is to review the back and my main interest is how well it performs and its new functionalities on high ISO and live view. Going on looking for problems is not my priority, if it comes up in normal type scenarios than fine let's talk about it but this is not going to be a head chopping block review out of the gate. Let's find the issues in the images and I'll be happy to expand on what I see or what I don't see. At the moment I see no main issues except maybe lens falloff at 18mm shifts but I think we can find a solution, sure a center filter would help a great deal. But honestly I'm Not going to focus on crosstalk unless it jumps out at us.
I'll be honest I'm not going to get into all this crosstalk business at all. The files will be available for folks to try and process themselves. My sole purpose is to review the back and my main interest is how well it performs and its new functionalities on high ISO and live view. Going on looking for problems is not my priority, if it comes up in normal type scenarios than fine let's talk about it but this is not going to be a head chopping block review out of the gate. Let's find the issues in the images and I'll be happy to expand on what I see or what I don't see. At the moment I see no main issues except maybe lens falloff at 18mm shifts but I think we can find a solution, sure a center filter would help a great deal. But honestly I'm Not going to focus on crosstalk unless it jumps out at us.
Guy Mancuso
Administrator, Instructor
Btw bushes here have different saturation even from the same family type. We have received a lot of rain lately so things have greened up. So not very accurate to go by. I have several building shots in full sun that look good in regards to color saturation between the other shots. One other thing is I have to watch the light falloff on the outside images. They do need to be adjusted just like other CCD backs do. 100 percent is not always accurate.
GrahamWelland
Subscriber & Workshop Member
Btw, when I bought my Alpa 40HR there wasn't a center filter option for it from Rodenstock. Did I miss something? Trust me, if there was stuff for that 40mm I'd have it - I've got it from the HPF rings, tilt adapter, Alpa hood etc but no mention of a center filter ...
What I meant with the comment is that you might get a different result with a different orientation of the sensor. I have no interest in chopping heads either, my interest is to thoroughly document how well this CMOS sensor behaves with the wide angle alternatives. I'm interested knowing when it performs well and when there may be issues.
I understand you're limited in testing abilities from the gear you have, it's okay. Do the tests you like.
Why I'm pushing this is because it's an extremely interesting alternative for view/tech camera users, a lot of folks wants live view badly. So bad that one might run to conclusion a bit too quickly. I don't want to scare people off, just make people be cautious. At some point a really thorough wide angle test would be nice, but that requires having lots of costly gear available which few have unfortunately. I've noticed a large variation on how picky people are about color and tonality issues so documenting exactly how the system performs would be helpful for people to make decision if the CMOS back is for them or not.
Doug's library test is good though, probably good enough for most people to make a decision. One thing missing in that however is the same stitch made with a vertical sensor too so one could see how it performs for vertical shots. Anyway, for those of you considering this back for wide angles do take a look at those files. Download the IQ260 32 HR shot and use as reference, and compare with the various IQ250 shots (HR40, HR32 and even SK35 is available, the SK35 shot is great to learn how to recognize crosstalk artifacts). Compare saturation, is colors more saturated closer to the center than farther to the sides? Look at the reference IQ260 shot and notice which colors that are the same around the ceiling, and then compare with the IQ250 shots and look for color variations. Colors that are the same in the IQ260 shot in various positions in the ceiling varies a bit on the IQ250. The variations are more severe farther out. Maybe the shift range you're interested in is okay.
Then consider that in landscape shots the effects will most likely be smaller than what you see in the library, as nature often has less saturated colors. One can also be of the opinion that colors accuracy and tonality is less important in nature as differences in light and moisture can get natural variations that look similar, and the viewer would not know how it looked there.
My guess is that most users will be happy with the HR40 performance. A bit fewer with the 32HR, but many still. Haven't seen any wider angle tests than those, except for the SK28 (which doesn't work at all of course). If you're not of the stitching kind a 40mm lens would be a bit long for the 44x33mm sensor, but possibly you would not need wider than 32mm. It's possible that the 28HR perform quite well too, as it could be more retrofocus than the 32HR.
There is a real possibility that quite a few users would be pleased with the performance of the CMOS on the Digaron-S 28, Digaron-W 32 and up. That opens up for a view/tech camera revolution. Thus it would be super-cool at some point get a thorough test of these lenses. I could do such a test of course, and I would combine very technical tests with real world testing to cater all tastes, but I'm unfortunately not in the position to come by gear for testing.
Oh, link to Doug's test: https://www.digitaltransitions.com/blog/dt-blog/phase-one-iq250-tech-camera-testing
I understand you're limited in testing abilities from the gear you have, it's okay. Do the tests you like.
Why I'm pushing this is because it's an extremely interesting alternative for view/tech camera users, a lot of folks wants live view badly. So bad that one might run to conclusion a bit too quickly. I don't want to scare people off, just make people be cautious. At some point a really thorough wide angle test would be nice, but that requires having lots of costly gear available which few have unfortunately. I've noticed a large variation on how picky people are about color and tonality issues so documenting exactly how the system performs would be helpful for people to make decision if the CMOS back is for them or not.
Doug's library test is good though, probably good enough for most people to make a decision. One thing missing in that however is the same stitch made with a vertical sensor too so one could see how it performs for vertical shots. Anyway, for those of you considering this back for wide angles do take a look at those files. Download the IQ260 32 HR shot and use as reference, and compare with the various IQ250 shots (HR40, HR32 and even SK35 is available, the SK35 shot is great to learn how to recognize crosstalk artifacts). Compare saturation, is colors more saturated closer to the center than farther to the sides? Look at the reference IQ260 shot and notice which colors that are the same around the ceiling, and then compare with the IQ250 shots and look for color variations. Colors that are the same in the IQ260 shot in various positions in the ceiling varies a bit on the IQ250. The variations are more severe farther out. Maybe the shift range you're interested in is okay.
Then consider that in landscape shots the effects will most likely be smaller than what you see in the library, as nature often has less saturated colors. One can also be of the opinion that colors accuracy and tonality is less important in nature as differences in light and moisture can get natural variations that look similar, and the viewer would not know how it looked there.
My guess is that most users will be happy with the HR40 performance. A bit fewer with the 32HR, but many still. Haven't seen any wider angle tests than those, except for the SK28 (which doesn't work at all of course). If you're not of the stitching kind a 40mm lens would be a bit long for the 44x33mm sensor, but possibly you would not need wider than 32mm. It's possible that the 28HR perform quite well too, as it could be more retrofocus than the 32HR.
There is a real possibility that quite a few users would be pleased with the performance of the CMOS on the Digaron-S 28, Digaron-W 32 and up. That opens up for a view/tech camera revolution. Thus it would be super-cool at some point get a thorough test of these lenses. I could do such a test of course, and I would combine very technical tests with real world testing to cater all tastes, but I'm unfortunately not in the position to come by gear for testing.
Oh, link to Doug's test: https://www.digitaltransitions.com/blog/dt-blog/phase-one-iq250-tech-camera-testing
Pemihan
Well-known member
I'm pretty sure there is no center filter for the 40HR.
That CMOS sensor has super-good DR never seen before in medium format which means that it can suffer quite some vignetting before it becomes a problem, so in a way it's less dependent on center filters. This also means that it can recover better than other backs from severe color casts. When color cast is severe there's a crosstalk component too though, which does affect color fidelity. In practical photography that's generally quite mild though.
Guy Mancuso
Administrator, Instructor
I don't think there is either but there is for the 28 and 32 roadie. I had the 28 myself. Nice nice lens
Guy Mancuso
Administrator, Instructor
Guess we need to try a find that limit.
I do think most folks shooting tech most likely have what I have on hand.
It would be highly desirable to see more testing with this back comibned with the Digaron-S 28 and Digaron-W 32 sometime in the future . I think most (but not all) will be happy with the Digaron-W 40 performance, but many won't be happy if that is the widest lens they can use.
From Doug's tests it seems Digaron-W 32 pushes it further, but still it can be good enough for many, and we don't know about the Digaron-S 28. It's not necessesarily worse than the Digaron-W 32 as you can make a lens more retrofocus to compensate the wider angle.
As I mentioned in a few posts back I think it's a real possibility that this CMOS back is the back for some wide angle shooters, but not yet for all. Need to balance my possibly negative-looking take on the back -- it's certainly not game over yet for the wide angle shooter. We just know that there are issues and they're still not so well-documented, and as long as this is the case it's good to be a bit cautious. For example if you think the Digaron-W 40 results look great but you plan later on to buy a Digaron-S 28, you should not "put in basket" before you actually get to see how the 28 performs too.
. I think most (but not all) will be happy with the Digaron-W 40 performance, but many won't be happy if that is the widest lens they can use.From Doug's tests it seems Digaron-W 32 pushes it further, but still it can be good enough for many, and we don't know about the Digaron-S 28. It's not necessesarily worse than the Digaron-W 32 as you can make a lens more retrofocus to compensate the wider angle.
As I mentioned in a few posts back I think it's a real possibility that this CMOS back is the back for some wide angle shooters, but not yet for all. Need to balance my possibly negative-looking take on the back -- it's certainly not game over yet for the wide angle shooter. We just know that there are issues and they're still not so well-documented, and as long as this is the case it's good to be a bit cautious. For example if you think the Digaron-W 40 results look great but you plan later on to buy a Digaron-S 28, you should not "put in basket" before you actually get to see how the 28 performs too.
Looking at Doug's 32 HR raw files I think one can get better results than I initially thought. I have not actually myself done a stitch of those files but only looked at the finished stitch made by someone at DT. Now I brought up a couple of the raw files in C1 and took a look. Few may be aware but this sensor has offset microlenses (or more correctly offset photo diodes) towards the sides so it can handle wide angles better. This assumes that the lens is centered though. It still helps when the lens is off center -- up to a certain point -- past that it suddenly breaks and you get very bad performance.
I've attached examples of 32 HR crop located at the upper part of an horizontal image shifted up 13mm. As you see the left 100% crop looks fine (possibly desaturated, don't know that, but if so not with much) while the right one look terrible, even with failed demosaicing artifacts. This is the same place on the image circle, but in the second case the sensor has been shifted more up. In the left the offset microlenses helps the sensor, in the right it breaks because the sensor is shifted too far up.
Thanks to the offset microlenses the back will probably perform quite well within a moderate shift range, but will suddenly break if shifted too far. The tricky part is that a fixed part of the scene that looked good with a lower amount of shift can start looking bad when you shift some more. This is a new effect, as none of the CCDs employ offset microlenses.
I think that whoever that did the DT example stitch did not know about this effect and may not have made an ideal stitch, ie some parts of the picture contains segments of a sensor shifted to far when you could have got a better render at that particular place in the image circle with the sensor in a different position. With optimal technique you could make it perform better.
It needs some figuring out what this technique should be and which guidelines to give. This sensor + wide angles is not the easiest to review... but I think if you handle everything carefully and never "overshift" it is possible that you can use both the 32HR and the 28HR with good results, perhaps not with reproduction-quality color fidelity but certainly fine for less demanding applications. It takes more testing to give any good answers.
For reference, this image illustrates offset microlenses concept:
I've attached examples of 32 HR crop located at the upper part of an horizontal image shifted up 13mm. As you see the left 100% crop looks fine (possibly desaturated, don't know that, but if so not with much) while the right one look terrible, even with failed demosaicing artifacts. This is the same place on the image circle, but in the second case the sensor has been shifted more up. In the left the offset microlenses helps the sensor, in the right it breaks because the sensor is shifted too far up.
Thanks to the offset microlenses the back will probably perform quite well within a moderate shift range, but will suddenly break if shifted too far. The tricky part is that a fixed part of the scene that looked good with a lower amount of shift can start looking bad when you shift some more. This is a new effect, as none of the CCDs employ offset microlenses.
I think that whoever that did the DT example stitch did not know about this effect and may not have made an ideal stitch, ie some parts of the picture contains segments of a sensor shifted to far when you could have got a better render at that particular place in the image circle with the sensor in a different position. With optimal technique you could make it perform better.
It needs some figuring out what this technique should be and which guidelines to give. This sensor + wide angles is not the easiest to review... but I think if you handle everything carefully and never "overshift" it is possible that you can use both the 32HR and the 28HR with good results, perhaps not with reproduction-quality color fidelity but certainly fine for less demanding applications. It takes more testing to give any good answers.
For reference, this image illustrates offset microlenses concept:
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Guy, about the three-stitch image you posted;
Due to the offset microlenses - you probably get the best stitching result if you use as much as possible of the center image (where offset microlenses will work best in helping improve the result), and for the left image you should use as little as possible of the right half (as there the microlens offset will counter-act the incoming light angle), and for the right image as little as possible from the left half for the same reason. Maybe it's already stitched that way, but anyway good to know.
Due to the offset microlenses - you probably get the best stitching result if you use as much as possible of the center image (where offset microlenses will work best in helping improve the result), and for the left image you should use as little as possible of the right half (as there the microlens offset will counter-act the incoming light angle), and for the right image as little as possible from the left half for the same reason. Maybe it's already stitched that way, but anyway good to know.
There is no Rodenstock CF. However Heliopan made a series of CF filters and the P/N 706751 works very well with the 40mm Rod.
67/86mm 1.5 stops. Schot glass optically very good.
Appears now to be discontinued but there are a few probably still floating around.
On the 40mm this filter does help on shifts of 12mm or more. Much less noise in the shifted sides with a CCD back.
Paul
Here's an illustration to show a bit clearer. For optimal result as much as possible of the red center frame should be used, and minimize the use of the overlapping segments of the green and blue frame. This makes the best use of the sensor's microlens offset.
Examining the overlapping segment, for example the one outlined in yellow, can be interesting. In a perfect system the colors would be exactly the same for both images, at least after white-balancing after a common point. I think the C1 LCC application can cause some white balance shift, so it may not match directly after LCC apply.
The sky seems to pick up some magenta cast towards the left side, I don't know if that's natural (depending on the sun's position the sky may not be 100% even) or if it's an artifact. Could be as simple as a white balance mismatch.
I know from previous testing that the sensor present very different color cast not only horizontal vs vertical but also if you turn the back upside down. This should be visible in your LCC shots. If the sensor behaves perfectly symmetrical the LCC shot from the green frame (left) should be the same as a mirrored blue frame (right), but I'm quite sure that's not the case, instead it will be more towards red on one side (the left?) and more towards blue on the other.
If the magenta cast of the left side sky indeed is a crosstalk artifact that effect may explain why it's not the same on the right side, on the left side you may get a bit more red/magenta, and on the right side a bit more blue/cyan.
There's a whole lot of speculation here though... I hope you'll share raw files at some point
The image does look great and natural. But say if the actual sky at the scene was indeed solid blue left to right and now it's not, is that an acceptable result? The greyer greens on the leftmost tree does not look unnatural, but if they in actuality was as green as the center bush, is that an acceptable result? For some it will, for others it will not. In the best case the greyer greens and the magenta left really was the look of the original scene, and that would be a lovely result. Unfortunately it's hard to nail down this for sure without lab-style testing, I have some results pointing towards that it should work, and others that are less positive. I don't really know what to think myself.
I think that the greyer greens and magenta can either be natural or just a white balance error, and if so I think the HR40 will make most users satisfied. And after taking another look at Doug's library test on HR 32 in C1 and making a stitch "microlens-offset-aware" I'm a bit more optimistic.
Personally I would however not get the back without lab-style testing with the full range of wide angles I have in mind, I would just hate it if I'd been shooting a year and then realize that wait a minute, I have color shift in many of my shifted images that I just did not notice at first. I know MF users generally dislike lab tests, but for things like slight color shifts and desaturation which this is about it's much more reliable to make a lab test than shooting live scenes. A simple lab test would be to shoot a color checker in center, and then move the camera and shift around and shoot the exact same setup in various shift combinations, then overlay and look for differences. Then you would know what kind of color shifts and desaturations we're looking at for which colors, and then one can go on shooting live scenes and relate to what we saw in the lab. If I was a dealer I would do it first thing, the whole issue is so complex (the offset microlens thing doesn't make it easier) that I don't think it's really fair to say to a potential buyer "make your own real-world tests and make up your mind", because it's so easy to make mistakes of the kind that you don't really notice anything when you do your casual tests but then over time you notice that maybe there's something with the color not doing so well.
This thread shows how such a color-checker lab test can look (for a different back / lens combination):
http://www.getdpi.com/forum/medium-...osstalk-cancellation-preliminary-results.html
(unfortunately the early crosstalk cancellation algorithm demonstrated in that thread did not work out for the kind of crosstalk we see in this CMOS, but maybe I'll make another attempt...)
Examining the overlapping segment, for example the one outlined in yellow, can be interesting. In a perfect system the colors would be exactly the same for both images, at least after white-balancing after a common point. I think the C1 LCC application can cause some white balance shift, so it may not match directly after LCC apply.
The sky seems to pick up some magenta cast towards the left side, I don't know if that's natural (depending on the sun's position the sky may not be 100% even) or if it's an artifact. Could be as simple as a white balance mismatch.
I know from previous testing that the sensor present very different color cast not only horizontal vs vertical but also if you turn the back upside down. This should be visible in your LCC shots. If the sensor behaves perfectly symmetrical the LCC shot from the green frame (left) should be the same as a mirrored blue frame (right), but I'm quite sure that's not the case, instead it will be more towards red on one side (the left?) and more towards blue on the other.
If the magenta cast of the left side sky indeed is a crosstalk artifact that effect may explain why it's not the same on the right side, on the left side you may get a bit more red/magenta, and on the right side a bit more blue/cyan.
There's a whole lot of speculation here though... I hope you'll share raw files at some point
The image does look great and natural. But say if the actual sky at the scene was indeed solid blue left to right and now it's not, is that an acceptable result? The greyer greens on the leftmost tree does not look unnatural, but if they in actuality was as green as the center bush, is that an acceptable result? For some it will, for others it will not. In the best case the greyer greens and the magenta left really was the look of the original scene, and that would be a lovely result. Unfortunately it's hard to nail down this for sure without lab-style testing, I have some results pointing towards that it should work, and others that are less positive. I don't really know what to think myself.
I think that the greyer greens and magenta can either be natural or just a white balance error, and if so I think the HR40 will make most users satisfied. And after taking another look at Doug's library test on HR 32 in C1 and making a stitch "microlens-offset-aware" I'm a bit more optimistic.
Personally I would however not get the back without lab-style testing with the full range of wide angles I have in mind, I would just hate it if I'd been shooting a year and then realize that wait a minute, I have color shift in many of my shifted images that I just did not notice at first. I know MF users generally dislike lab tests, but for things like slight color shifts and desaturation which this is about it's much more reliable to make a lab test than shooting live scenes. A simple lab test would be to shoot a color checker in center, and then move the camera and shift around and shoot the exact same setup in various shift combinations, then overlay and look for differences. Then you would know what kind of color shifts and desaturations we're looking at for which colors, and then one can go on shooting live scenes and relate to what we saw in the lab. If I was a dealer I would do it first thing, the whole issue is so complex (the offset microlens thing doesn't make it easier) that I don't think it's really fair to say to a potential buyer "make your own real-world tests and make up your mind", because it's so easy to make mistakes of the kind that you don't really notice anything when you do your casual tests but then over time you notice that maybe there's something with the color not doing so well.
This thread shows how such a color-checker lab test can look (for a different back / lens combination):
http://www.getdpi.com/forum/medium-...osstalk-cancellation-preliminary-results.html
(unfortunately the early crosstalk cancellation algorithm demonstrated in that thread did not work out for the kind of crosstalk we see in this CMOS, but maybe I'll make another attempt...)
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Guy Mancuso
Administrator, Instructor
Folks Im working on the review . i know you see it on the forum Its locked for now until I get more data up but downloads are there and i hate working alone. LOL
Thanks Guy.
A question though, is the straight non stitched shot taken with the 40mm HR with fall of the back? Just trying to gauge how it might suit my purposes, as I never stitch but want and need to perform perspective correction in camera. I'd need a 32 HR to cover my work though. Any thoughts on how that lens would perform compared to the 40 HR?
Thanks again for your time and effort on this.
TJV
A question though, is the straight non stitched shot taken with the 40mm HR with fall of the back? Just trying to gauge how it might suit my purposes, as I never stitch but want and need to perform perspective correction in camera. I'd need a 32 HR to cover my work though. Any thoughts on how that lens would perform compared to the 40 HR?
Thanks again for your time and effort on this.
TJV