Is the IQ180 the end for Schneider lenses ? compared to Rodenstock

[Terry]

Chris, those results with the 28mm are quite a surprise to me and look really clean considering its such a wide lens. I'd be really happy with 10mm of movement with this lens. I thought the new 28mm super digitar however was a retrofocus design lens so possibly helping with the issue compired to the usual symetrical Schneider wide lens designs (35XL and 43XL).

But that is also on a P40+ which has two things in it's favor vs IQ180. Larger pixels and smaller sensor.

 

[Bob]

But that is also on a P40+ which has two things in it's favor vs IQ180. Larger pixels and smaller sensor.

I am not sure that it is really "in favor"
I propose that the field of view expressed as an angle will be the same.
You just need longer lenses to get there.
-bob

 

[Jack]

I spent some time yesterday shooting "real world" landscapes with the Arca RM3D and Schneider 43 in front of my IQ180 back.

I won't bore you with the "ugly" LCC frames since they looked just like the others posted here other than to say I found that LCC using "Analyze Technical Wideangle" in C1 6.2 worked perfectly well up to 20mm of shift on this lens. At 20mm however, the lens itself starts falling apart to where the corners are very visibly bad. Probably about 17mm is the maximum practical shift with this lens on full frame, regardless of sensor. IMHO given the fact LCC is totally usable there with this lens on the IQ180, I think the combination issue is pretty much nullified. However, falloff is pretty extreme in this lens at 15mm of shift, showing about 2 stops at the shifted edge. Since falloff with that much shift can be in a significant portion of the image that includes highlights, the LCC falloff correction can cause an otherwise good full frame histogram to blow those highlights after correction. (Falloff in technical wideangle lenses can act like a Split Neutral Density filter for skies, and thus influence the histogram giving you false confidence. This is favorable for things like bright skies, but not necessarily for the rest of the tones in the image below the 3/4 mark.) Thus for this lens, I'd recommend getting a physical center filter to help reduce the load on the LCC for making the extreme correction by itself, also rendering a more realistic histogram spread. Other option is to leave about a full stop of exposure headroom if you shift 10mm or more.

Usage Note: Setting focus mask at 40 makes for a comfortable indication of accurate focus. Moving it up to 45 renders a tighter and narrower indication, and my preference might be 48 or so for those wanting maximum criticality. Confirming with a double-tap to 100% is still recommended until you get comfortable with reading the system.

I am trying to get my hands on a Rodenstock 40 HR-W in Arca mount to test this coming week.

 

[cng]

LCC using "Analyze Technical Wideangle" in C1 6.2 worked perfectly well up to 20mm of shift on this lens. At 20mm however, the lens itself starts falling apart to where the corners are very visibly bad. Probably about 17mm is the maximum practical shift with this lens on full frame, regardless of sensor. IMHO given the fact LCC is totally usable there with this lens on the IQ180, I think the combination issue is pretty much nullified.

Just doing some very quick rough numbers in my head, does this then mean the useable IC of the Schneider 43mm is comparable to/slightly more than the official IC for the Rodenstock 32mm HR-W (and of course much less than the 43mm's official specs)? So we effectively still gain a few more mm of movements compared to the Rodenstock, ignoring the fact that the 32mm HR-W may actually have a larger IC than officially quoted.

 

[Woody Campbell]

I spent some time yesterday shooting "real world" landscapes with the Arca RM3D and Schneider 43 in front of my IQ180 back.

I won't bore you with the "ugly" LCC frames since they looked just like the others posted here other than to say I found that LCC using "Analyze Technical Wideangle" in C1 6.2 worked perfectly well up to 20mm of shift on this lens. At 20mm however, the lens itself starts falling apart to where the corners are very visibly bad. Probably about 17mm is the maximum practical shift with this lens on full frame, regardless of sensor. IMHO given the fact LCC is totally usable there with this lens on the IQ180, I think the combination issue is pretty much nullified. However, falloff is pretty extreme in this lens at 15mm of shift, showing about 2 stops at the shifted edge. Since falloff with that much shift can be in a significant portion of the image that includes highlights, the LCC falloff correction can cause an otherwise good full frame histogram to blow those highlights after correction. (Falloff in technical wideangle lenses can act like a Split Neutral Density filter for skies, and thus influence the histogram giving you false confidence. This is favorable for things like bright skies, but not necessarily for the rest of the tones in the image below the 3/4 mark.) Thus for this lens, I'd recommend getting a physical center filter to help reduce the load on the LCC for making the extreme correction by itself, also rendering a more realistic histogram spread. Other option is to leave about a full stop of exposure headroom if you shift 10mm or more.

Usage Note: Setting focus mask at 40 makes for a comfortable indication of accurate focus. Moving it up to 45 renders a tighter and narrower indication, and my preference might be 48 or so for those wanting maximum criticality. Confirming with a double-tap to 100% is still recommended until you get comfortable with reading the system.

I am trying to get my hands on a Rodenstock 40 HR-W in Arca mount to test this coming week.

Jack - Thanks for the report. Have you tried including an X-rite color checker at the shifted edge that's furthest from the center of the image circle to check color accuracy/saturation? Also testing at higher ISO might give an indication if the LCC adjustment in or near the "blue zone of death" is adding noise. Again I'm guessing but I think base ISO is going to be mandatory when shooting with significant shifts, which is ok because by hypothesis you are working on a tripod.

 

[Jack]

Just doing some very quick rough numbers in my head, does this then mean the useable IC of the Schneider 43mm is comparable to/slightly more than the official IC for the Rodenstock 32mm HR-W (and of course much less than the 43mm's official specs)? So we effectively still gain a few more mm of movements compared to the Rodenstock, ignoring the fact that the 32mm HR-W may actually have a larger IC than officially quoted.

Let me just say I feel the spec is using a very loose definition for both LinePairs and contrast ratios at the outer edges of the stated IC. I would state that the lens ILLUMINATES well beyond what I consider its usable IC

 

[Jack]

Jack - Thanks for the report. Have you tried including an X-rite color checker at the shifted edge that's furthest from the center of the image circle to check color accuracy/saturation? Also testing at higher ISO might give an indication if the LCC adjustment in or near the "blue zone of death" is adding noise. Again I'm guessing but I think base ISO is going to mandatory when shooting with significant shifts, which is ok because by hypothesis you are working on a tripod.

I did not do either Woody. I think using a tech cam at other than base ISO is counter productive in real life situations, but what you suggest is good for academic knowledge. But bottom line using my 2-stops margin measured for the falloff on this lens, knowing LCC needs to boost that by 2 stops, and knowing that the IQ180 is okay at ISO 800, I would say the practical max ISO will be 200 (800 edges), with 100 (400 edges) being totally usable. Having the Passport in the edge of the frame would be relevant useful data too. I'll try and set a simple shot up outside today and do both.

 

[cng]

Let me just say I feel the spec is using a very loose definition for resolution at the outer edges of the stated IC

Politician in the making. :toocool:

Luckily I need the movements for the brute work of dealing with converging verticals, rather than stitching, so I can potentially sacrifice some resolution at the edges. I'd rather not, but them's the breaks.

The Schneiders' greater freedom from distortion still wins for me, with the inescapable trade-off of sensor casts. There's always some element of post-capture work to be done regardless of lens, camera, back or user.

Thanks very much Jack, Guy, Woody, Christopher and the guys at CI (have I forgotten anyone?) for all the testing.

 

[Jack]

Okay, here you go Woody:

This is pretty extreme ugly capture conditions from a technical standpoint for noise and LCC correction combined. 43mm Schneider shifted 12mm left, the max lateral shift in the RM3D I am using, shooting into a shady area so we get the max boost from the LCC at the dark corner. This is ISO 400 on the IQ180, and 1/15th at f11 on the lens. Note too that the Sun is just off camera right behind the cabin to the right basically shining on me as I shoot. Even though it isn't visible to the sensor, it is inside the lens' IC and tossing a boatload of light into the camera. That generates a strong flare in the upper LH corner and less in the upper RH corner. Noise is overly significant as I suspected, probably around net ISO 1600 in the corner after LCC boost. I would advise to use ISO 100 max if you plan on shifting -- and obviously, using ISO 35 would be even better. Note I used my standard (slightly warm) outdoor WB for all of these examples and did NOT dropper the passport! In addition to the noise making it unreliable at that small size, I have a bunch of light reflecting in on the passport from trees, dirty deck and parked cars.

Edit note: Since the Sun is shining basically on me and the camera form the front right, the LCC for this frame required the exact same exposure as the image to render a centered histo from the LCC. Using my normal 2 stops over, the LCC was pretty much all high gray.

First we have the un-corrected ugly to show I have the passport in a pretty bad area from an LCC PoV:

Now here is the LCC corrected frame. I am actually surprised (and sort of impressed) the LCC did not try to correct out the flare:

Here is the passport crop after the LCC. As you can see, noise is bad at probably around 1600 or more effective net ISO after LCC boost, and renders the passport basically unusable as a WB tool in that area of the frame. However, the overall saturation remains very respectable to my eyes, and not "killed" by the LCC as we feared it might be:

So I'll go on record with my conclusion:

If you push to the extreme outer limits of the lens IC or use extremely high ISO's with moderate shifts, you may not be satisfied with the LCC result. However, when used in realistic shooting conditions with proper technique for highest image quality, LCC corrects even significant lens and sensor color cast anomalies exceptionally well.

 

[Woody Campbell]

Okay, here you go Woody:

This is pretty extreme ugly capture conditions from a technical standpoint for noise and LCC correction combined. 43mm Schneider shifted 12mm left, the max lateral shift in the RM3D I am using, shooting into a shady area so we get the max boost from the LCC at the dark corner. This is ISO 400 on the IQ180, and 1/15th at f11 on the lens. Note too that the Sun is just off camera right behind the cabin to the right basically shining on me as I shoot. Even though it isn't visible to the sensor, it is inside the lens' IC and tossing a boatload of light into the camera. That generates a strong flare in the upper LH corner and less in the upper RH corner. Noise is overly significant as I suspected, probably around net ISO 1600 in the corner after LCC boost. I would advise to use ISO 100 max if you plan on shifting -- and obviously, using ISO 35 would be even better. Note I used my standard (slightly warm) outdoor WB for all of these examples and did NOT dropper the passport! In addition to the noise making it unreliable at that small size, I have a bunch of light reflecting in on the passport from trees, dirty deck and parked cars.

Edit note: Since the Sun is shining basically on me and the camera form the front right, the LCC for this frame required the exact same exposure as the image to render a centered histo from the LCC. Using my normal 2 stops over, the LCC was pretty much all high gray.

First we have the un-corrected ugly to show I have the passport in a pretty bad area from an LCC PoV:

Now here is the LCC corrected frame. I am actually surprised (and sort of impressed) the LCC did not try to correct out the flare:

Here is the passport crop after the LCC. As you can see, noise is bad at probably around 1600 or more effective net ISO after LCC boost, and renders the passport basically unusable as a WB tool in that area of the frame. However, the overall saturation remains very respectable to my eyes, and not "killed" by the LCC as we feared it might be:

So I'll go on record with my conclusion:

If you push to the extreme outer limits of the lens IC or use extremely high ISO's with moderate shifts, you may not be satisfied with the LCC result. However, when used in realistic shooting conditions with proper technique for highest image quality, LCC corrects even significant lens and sensor color cast anomalies exceptionally well.

Nicely done Jack. The color saturation and accuracy are very good under the circumstances - note that the color correction squares on the left come off as distinguishable. On the noise, going back to base ISO should help a lot, and a CW filter should make a big difference - allowing a 1.5 or 2 stops more exposure on the left edge. Real food for thought here.

 

[Jack]

Thanks Woody -- yes, there is zero conversion noise I can find at base ISO.

Here is another exlemplar of how good LCC is. You see how bad the casts are in the above lateral shift. Here is two frames at each end of the full 12.5mm L&R shift in each direction. These look just as bad as the one above before LCC. I purposely put the tree in the center front so we could see any hint of parallax shift if there were any -- there isn't, it's a perfect stitch as we expect from tech cameras with rear shifts and lens remains stationary. Note it's a blustery day here, the wind is blowing, rain off and on and the Sun is moving in and out of clouds, so I had to work really fast to get relatively even lighting. My process was, capture far L, add 2 stops, capture LCC, shift full R and capture image, then add 2 stops and capture LCC. Process each LCC in C1 and apply to each image. Make sure each image has identical settings and their proper LCC, process out as full 16-bit tiffs. Talk about stressing the laptop LOLOL! I then brought them into CS for a merge and got this perfect result. Folks, this is pretty impressive, I did not use the center frame capture; it simply isn't needed. Final file would print out natively at 21 x 44 inches at 360 PPI, and is roughly a 17mm lens FoV in 35mm terms:

 

[Woody Campbell]

Politician in the making. :toocool:

Luckily I need the movements for the brute work of dealing with converging verticals, rather than stitching, so I can potentially sacrifice some resolution at the edges. I'd rather not, but them's the breaks.

The Schneiders' greater freedom from distortion still wins for me, with the inescapable trade-off of sensor casts. There's always some element of post-capture work to be done regardless of lens, camera, back or user.

Thanks very much Jack, Guy, Woody, Christopher and the guys at CI (have I forgotten anyone?) for all the testing.

On distortion gon't give up on the Rodenstocks yet - next week I plan on sorting out how well the Alpa correction tool works with them.

 

[Woody Campbell]

Thanks Woody -- yes, there is zero conversion noise I can find at base ISO.

Here is another exlemplar of how good LCC is. You see how bad the casts are in the above lateral shift. Here is two frames at each end of the full 12.5mm L&R shift in each direction. These look just as bad as the one above before LCC. I purposely put the tree in the center front so we could see any hint of parallax shift if there were any -- there isn't, it's a perfect stitch as we expect from tech cameras with rear shifts as the lens remains stationary. Note it's a blustery day here, the wind is blowing, rain off and on and the Sun is moving in and out of clouds, so I had to work really fast to get relatively even lighting. My process was, capture far L, add 2 stops, capture LCC, shift full R and capture image, then add 2 stops and capture LCC. Process each LCC in C1 and apply to each image. Make sure each image has identical settings and their proper LCC, process out as full 16-bit tiffs. I then brought them into CS for a merge and got this perfect result. Folks, this is pretty impressive, I did not use the center frame capture; it simply isn't needed. Final file would print out natively at 21 x 44 inches at 360 PPI, and is roughly a 17mm lens FoV in 35mm terms:

Also a tough test for the lens on purple fringing.

 

[Terry]

Jack- this one stitch has done wonders to put my mind at ease. For me my typical use of the tech camera would involve stitches like this along with minor shifts to help my framing.

Thanks!




.

 

[Jack]

Purple fringe -- good call. Maybe just the barest hint?:

 

[Jack]

Jack- this one stitch has done wonders to put my mind at ease. For me my typical use of the tech camera would involve stitches like this minor shifts to help my framing.

Thanks!

That's why I did it --- LOLOLOLOL!

 

[Woody Campbell]

Purple fringe -- good call. Maybe just the barest hint?:

desaturate purple a bit and it goes away, generally without any other consequences in the image.

 

[Jack]

desaturate purple a bit and it goes away, generally without any other consequences in the image.

''

In C1 we have a built-in tool to remove it -- I did NOT use it on these conversions, so you are looking at the "real deal" as far as fringing on that lens/sensor combo goes.

 

[cmb_]

Another useful part of the LCC correction tool in C1 is that there is a slider to control the amount of Light Falloff correction you wish to apply (0 - 120 %) which may be useful in striking a balance between the amount of "acceptable noise" and exposure boost from the LCC correction. This may may not be useful for all types of stitched images, however, but on single frame images it could help and I often prefer some vignetting anyway.

 

[goesbang]

Most people aren't using these on tech cameras and ought to be very happy with the 180.

I own P65+, Aptus 12 and IQ 180 backs. I haven't had time to do much testing yet but without a doubt, both 80MP backs require a lot more LCC correction to be usable. The latest tech-cam LCC option is a massive step forward from the previous generic LCC. Keep in mind this is Gen 1 for this algorythm, so I'd imagine more updates to come, especially in light of the firestorm that's ignited.
Some of us will recall that the early LCC algorithyms for the P65+ needed more work.
I earn 90% of my income with a tech cam, so I will be watching closely and testing lots.

Cheers,