Rod 40mm IC

[JoeKitchen]

Rodentsock lists the IC of their 40mm HR lens as being 90mm big.  I know that Rodenstock has a tendency to be more conservative here; is the IC really only 90mm, or is slightly bigger? 

Also, does the 40mm HR have that internal ring that cuts the IC off like in some of the other HR lenses? 

I ask because I am trying to compare the SK 43mm to the Rod 40mm and the amount of shift each actually has. 

[Ken R]

Rodentsock lists the IC of their 40mm HR lens as being 90mm big.  I know that Rodenstock has a tendency to be more conservative here; is the IC really only 90mm, or is slightly bigger?  

Also, does the 40mm HR have that internal ring that cuts the IC off like in some of the other HR lenses?  

I ask because I am trying to compare the SK 43mm to the Rod 40mm and the amount of shift each actually has.  

I have the 40mm HR-W and yes it has an abrupt transition at the end of the image circle which indicated it has the internal disc or ring. With my IQ160 in horizontal I can max out the 15mm of horizontal L/R shift on my Arca and get just a bit of dark corners. I can look up some images tonight and post them. The Image Quality itself is superb almost to the very last mm of the image circle which makes it usable almost in its entirety which is awesome. Overall it is an incredible lens and I love the way the "focus" falls of from the point of focus at any aperture, it is very nice and smooth. Hard to explain. The lens is sharpest at f4-f8 but at f11 is still almost as sharp but at f16 it starts to get quite soft (I now never use it past f11) The sharpness of this lens shocked me. I have never used a lens this sharp with so little to no CA at any aperture. It is ridiculous. Makes most SLR lenses look like toys. It is also very easy to filter (I use Schneider 100mm rectangular filters) and honestly mine has only flared when I had a large HMi fresnel in the edge of the frame.

[JoeKitchen]

How about distortion?  I am concerned about this since I shoot architecture. 

[Paul2660]

Just to 2nd Ken's comments, the 40 HR-W is an excellent lens.  I used the 43SK for about 2 years before I tried the 40 and wish I had moved sooner.

On a P45+ either lens will work fine, and you can actually get more useable shift from the SK43 as it doesn't have the internal marker to show the limit of the image circle.  The P45+ will also not have any tiling issues on the SK43 or crosstalk problem.

With a Dalsa, 60MP things get a bit different.

The SK43 will get to about 12mm of useable shift.  Certain shots allowed me to get to 15mm of shift and I tried 18mm, but the loss of color and detail made it pointless.  The SK43 benefits from a CF on shifts, on center it's OK.  The SK43 will possibly have micro lenses rippling that the LCC and C1 can't totally correct.  You can also expect to see some tiling, but it's always hard to know when and where it will show up.  Most times I was able to remove the tiling in CS.  The LCC most times will not correct it when it get bad on shifts.

The 40mm Rodenstock, can get to 15mm of shift easily, however I have found that I am using a Heliopan CF on it now, to help keep the noise on edges down.  You hit the marker past 15mm and it becomes a very hard vignette at around 18mm or so.  The micro lens ripple most times will correct with the LCC and is not as common as on the 43SK.  Tiling is also less problematic, but at times I still get a line that C1 can't remove.  Cross talk on extreme shifts to 15mm is recoverable in most cases.  HOWEVER, I strongly feel that C1 currently doesn't do a perfect job on the color correction on shifts with a blue sky as I often still see a faint red cast towards far left or right sides of 15mm shifted images.  I will use C1 adjustment layers to remove that.   You should get a bit more rise fall on the 40mm before hitting the marker due to the layout of the Phase One chips.

I do see CA on extreme shifts to 15mm which surprises me but so far C1 seems able to handle this. 

My lens, is not very good at F4 to F8 -1 stop in that the hyperfoacal distance is much further out (tilt won't correct this in most of my shooting environments).  I feel that my lens is best from F8 to F11 +2, past that you start to see diffraction setting in. 

Flare, can be a problem, I use the Lee wide angle hood on mine or the CF which also seems to help. 

The 43SK is much lighter, is a better travel lens, and considerably less delicate.  The Rodenstocks are heavy and have a lot of weight in front of the copol so you have to be more careful in handling them.

I did not want to go to a CF on the 40, but as with the 43SK it makes a considerable difference in noise on extreme shift of 12mm to 15mm, even at base iso 50.  This is more problematic for me in the summer when I am working in 85 to 104 heat and the back is getting very warm. 

I have not seen the ghost flare problem that my 90mm Rodenstock is plagued with and I really have to watch for in the field.

Paul

[Doug Peterson]

You can see the entirety of the image circle as single stitched image, with guides shown for image circle size and rise/fall/shift amounts for the IQ250, IQ260, and IQ280 here:
https://digitaltransitions.com/blog/dt-blog/phase-one-iq250-tech-camera-testing

Using that JPG you can come to your own conclusion about image circle size that you are happy with. Our assessment, if you're feeling lazy, or just want a second opinion, is also in the article.

[torger]

Concerning distortion, from the data sheets:

The Digaron-W 40 distorts about -1.4%
The Digitar 43 distorts about -0.5%

To have something to compare with, a Canon TS-E 24 II distorts -0.9% on 135 full-frame, which is considered really good on that format, while the regular 24mm II has -1.4%.

Negative means barrel distortion. I'd say 1.4% is "moderate" distortion, 0.5% is very slight. You may want to correct the Digaron-W when you shoot architecture. I know some even correct the Digitar 43, but I would probably not do so.

[JoeKitchen]

You can see the entirety of the image circle as single stitched image, with guides shown for image circle size and rise/fall/shift amounts for the IQ250, IQ260, and IQ280 here:
https://digitaltransitions.com/blog/dt-blog/phase-one-iq250-tech-camera-testing

Using that JPG you can come to your own conclusion about image circle size that you are happy with. Our assessment, if you're feeling lazy, or just want a second opinion, is also in the article.

Thanks Doug.  Very nice IQ on the 40mm.

[torger]

As we discussed in the Digitar thread the Digaron-W 40 is more future-proof, it's the one you want to have on 6um Dalsa backs. If you intend to keep the P45+ for a long time or go to a 50 MP Kodak chip on Hasselblad then the 43 could be a better choice, but it will be a little bit less sharp on extreme shifts.

Personally I like the Digitar design tradeoffs better, but sensor support is not optimal. I'd go for the Digaron-W 40 if I intended to upgrade to an IQ260, and go with the 43 if staying on the Kodak chips.

[JoeKitchen]

As we discussed in the Digitar thread the Digaron-W 40 is more future-proof, it's the one you want to have on 6um Dalsa backs. If you intend to keep the P45+ for a long time or go to a 50 MP Kodak chip on Hasselblad then the 43 could be a better choice, but it will be a little bit less sharp on extreme shifts.

Personally I like the Digitar design tradeoffs better, but sensor support is not optimal. I'd go for the Digaron-W 40 if I intended to upgrade to an IQ260, and go with the 43 if staying on the Kodak chips.

Everything seems to be a trade off, but in terms of future proof, the 40 sounds like a better lens, even though I like the specs of the 43mm.  In any event, the 40mm is about the angle of view on an IQ260 as a 35mm on a P45+, so maybe having only 20mm of shift would not be that big of a deal. 

Now if only the 50mm had a larger IC than 90mm, like similar to the 43mm.  If so a 32, 40, 50 would be my perfect line up on the IQ260. 

I do have the Rod 55mm though, which has a very large IC, but sharpness fall off is a concern after 15mm of shift. 

[pemihan]

The 40mm Rodenstock, can get to 15mm of shift easily, however I have found that I am using a Heliopan CF on it now, to help keep the noise on edges down. 

Paul, exactly which CF are you using?

Peter

[Paul2660]

Peter,

It's this one:

http://www.bhphotovideo.com/c/product/21722-REG/Heliopan_706751_67mm_Center_ND_3x.html

It goes from 67mm to 86mm, thus it won't work with the Lee wide angle hood as Lee only makes a 86mm standard ring.  Standard ring vignettes. 

I have found in many shots it makes a considerable difference on shifts from excessive noise to almost none.  I believe it's 1.5 stops of light, not too much and it takes me only about 1 aperture stop in the field, which most times is manageable. 
Where I found it invaluable is when I am forces to iso 140 on the IQ260 for shutter speed issues.  Iso 100 or 140 to me are basically the same in response but do get very noisy when shifted (at least in my findings here in late spring and summer).  This filter is not a bad compromise. 

I can step it up with either a 86 to 105 and use a CLPL (105mm) or I have adapted a standard Lee 95mm to 105mm 2 filter holder to work also. Both sadly cost me about 2mm of shift, but the image quality is to me worth it.

Paul

[pemihan]

Thanks for the info Paul...

Peter

[jsiva]

Joe, I would check the close focusing limit for each lens based on the mount you're looking at.  I am pretty sure the Rodie focuses closer, at least on the RM3Di.  I do have the Rodie and it is a great lens on the IQ180.

Another option is the 60XL, though it may be too long. Great lens, and lots of shifting room.  LCC is not too extreme either.