The 550 XXL is what the lens was on the picture of my son Satchel Cochise. Shot wide open at f11 from about one meter away give or take.
Monty
The 550 XXL is what the lens was on the picture of my son Satchel Cochise. Shot wide open at f11 from about one meter away give or take.
Monty
I feel very fortunate to have the opportunity to use and be the temporary custodian in time of this lens. In terms of what it can do in the world of ULF it is truly a unique piece of glass.Originally Posted by robert
Sandy
Monty. That is really a great picture of your son.
Sandy
Thank you Sandy.
Monty
I'll echo that too... beautiful!!
Sandy, nice find, where did you get these MTF charts? I wish you had the same for the 1100mm XXL also...
These MTF curves are very interesting IMO, as these Fine Art XXL lenses had all the benefits of the newest glass types available, surfacing techniques, computer design optimization and high tolerancing machining, high tolerance testing, etc. None of these were available back when ULF was the Soup-de-jour. So IMO, this this lens design might represent the limitations in making lenses with such huge coverage, even with all the modern design tools, glass types and manufacturing techniques available to the lens designer. Considering the price of these lenses (~$10k for the pair), I would suggest that Schneider dedicated a lot of R&D into this lens set. And Kudos to Schneider for even making such lenses in these times. Also, this is the first MTF chart I have ever seen on a lens of such massive coverage. It's possible, it may be the only MTF data that exist with 900mm image circle? Hence, I was interested in comparing it to other lenses.
It's hard to express details without lots of numbers and math.... so I will generalize some of my comments to avoid irritating many... (I would love to hear others comments also) Also, keep in mind, this 550 XXL is WA lens, this has pros and cons. The pros are, as discussed previously, shorter fl's have huge advantages...the Cons are, when shorter fl's fall into the WA category, the image quality at ~ 50% out on the radius, degrades rather fast. This is true with most all lenses, except with some of the BEST newest WA designs, such as the Digitar 35 / 47 and Mamiya 43mm, as well as the SSXL110 and 150. (I am sure there are a few others, these are the ones that come to mind)
550 XXL
Lens coverage is 900mm diag. Quite impressive. 20x24 = 800mm
Light fall off - about 1 stop at 50% of the radius (image circle radius), almost 2 stops at full coverage (varies bases on f stop, just an avg.)
Distortion at 80% radius, .5%, quite impressive.
Resolution:
The MTF values provided are for f11,22 and 45. For a lens of this coverage, I would have preferred to have seen f45/64/90, but.... this is what they provide. This lens is CLEARLY an f45+ lens (although without seeing higher f numbers, can't be assured of the values)
There is some debate on how to convert MTF to aerial resolution, (it's not an exact science) so I don't want to open up that can of worms. So, some general comments about the lenses performance...
IMO, the simplest way to gage the performance of this lens, is to compare it, on a relative basis to other LF lenses. The reason is, the MTF of the lens is NOT the lenses measured aerial resolution.....which was the basis of the previous discussions. Instead, the MTF value expresses what % of the targets contrast will be transmitted by the lens. To create an apples to apples comparison, I will pick 60% contrast transmittance value for all lenses compared. Higher resolving lenses have the ability to transmit higher l/mm targets, at the same 60% contrast transmittance. So we will use the l/mm value as the comparative factor. (I tried to avg. rad. and tang. values) I will also try to select each lenses sweet spot, (f stop and focus distance) to shorten this post. Also, these are the values AT the focus distance only - throughout the entire image circle. MTF does not consider DOF issues.
I will use the following image circles.... shooting for the bulk of a formats area, (forgoing the corners) by using only the long dimension of each format...
4x5 = 125mm
8x10 = 250mm
11x14 = 350mm
16x20 = 500mm
So here is the MTF values, stated in l/mm on avg. at the following image circles ....(some estimating here)
125mm/250mm/350mm/500mm+
The 125mm refers to the center 125mm image circle, the 250, refers to the area between 125mm and 250mm, the 350mm refers to the area between 250mm and 350mm..... This should give a good feel for the resolution capability per format size. However, this is NOT a chart of lens coverage for a format size.... (trying to cut down on the number of variables here) "x" designates, not enough coverage, so no resolution...
10/10/6/2 - Fine Art XXL 550mm fl
20/18/x/x - APO Symmar 150L (will not cover 810)
Similar results for Super Angulon 90/6.8
20/20/10/x - Super Symar XL 150 (Aspherical) covers 810
20/20/15/x - APO Symar 300L
20/20/15/x - APO Symar 480 (500mm image circle)
30/x/x/x - Digitar 210 6.8 (120mm image circle)
Similar results for 180 Digitar, same image circle.
40/x/x/x - Digitar 80, only 80mm image circle,
only used to demonstrate relationship
between image circle and resolution.
My prelim. thoughts....
As expected, even with all the modern tools / glass at the designer disposal, it seems with current optical technology, there is a huge price one pays in over-all lens performance when gaining coverage in the 500 - 900mm image circle range. Simple example is comparing the APO Symar 480 vs. the 550 XXL. The 480 will cover 11x14.... you can 2x enlarge the 11x14, = 22x28.... and still be ahead in the resolution department vs. shooting 20x24 with the 550 XXL (divide the 480's numbers by 2). Yes, different composures if the camera is in the same location, but without the 1100mm XXL MTF values, this is the best we have to work with to compare.
I still believe 8x10 benefits the most from current lens technology, as the fall-off becomes significant after this level...and if one is not forced to stop down far for extreme DOF, this format has the largest selection of lenses and a relatively compact system (as it relates to ULF) Just compare the pix above with the 16x20 in the guys trunk, vs. a person backpacking with 810. Of course, when DOF is big variable, 4x5 is still the most versatile of all formats.
Also, notice the Digitars amazing resolution, but of course, at the expense of a smaller image circle. The beauty here is, this is combined with super high resolving recording sensor, as discussed earlier. Surely a trend that will continue.
Also, MTF values is an optical expression of lens performance. It was not created for the photographic field, so the charts are not as photo friendly as many would like. But they do contain very useful data. My methodology above was my "best attempt" to present MTF data in a means that photographers can more easily relate to. I did some approximations along the way. If you have a better method to express this data, please do present it. Overall, IMO, an interesting exercise ....
DISCLAIMER: this post only relates to lens performance as it relates to format size. This post does NOT make any implications of what format is the right choice for each person. For that decision, as discussed above, there is many other factors, in which, "I GET" !! The event of setting up, the thrill of the gg view, the relationship with the people you shoot, the desire to make contact prints, NOT enlargements, the methodical approach, etc. etc. etc. Lens and resolution performance is ONLY one of many variables one should consider as it relates to format selection. (as thorough as I feel this disclaimer is, I will probably still get clobbered)
Hey bglick, thanks for your interesting and informative post. You mentioned distortion at 80% radius on the 550 XXL being about 0.5%. What kind of distortion are you referring to; non rectilinear (pincushion or barrel type). Just curious.
Nate Potter
Pin cushion...
Here you go!
Thanks Eric!
As expected, the 1100 performs slightly better.... same image circle coverage of 900mm. Distortion not worth discussing, very impressive. Light fall off, very marginal.
Using the same methodology as above....
12/12/10/5 - Fine Art 1100mm XXL
I would consider this a very impressive lens for ULF, specially 16x20 format (or other rectangular formats with the same diag.) When compared to the 550 XXL, which would probably demand use of a ND center filter, this lens will also gain ~1.5 stops of shutter speed.
Focussed at infinity, at f45, on 16x20 or equiv., this is probably the sharpest image one record with one click of the shutter. Very impressive...
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