SK 35mm and 28mm with Credo 40 or 60?

[gebseng]

Hi everyone,

I consider upgrading from my almost ancient Leaf Aptus 75S to a more recent Leaf Credo 40 or 60. Pixel count is not much of an issue here, the current 33MP are just fine 95% of the time.The main reason for switching is in-camera live view, which would redeem me from shooting tethered with a 11" macbook air (I shoot architecture almost exclusively).

My main lens now is my beloved SK 35/5.6 Digitar with centerfilter (we get along really well after some midterm difficulties and seeing a couples therapist). So, if possible, I would like to keep that lens with the Credo 40 or 60, since the sensor dimensions are only 10% shorter (with the 44x33mm Credo 40 sensor) or 10% longer (with the 40x53mm Credo 60), and I think I can live with the slightly more narrow/wide FOV.

The (very helpful!) "Tech Camera Overview" on digitaltransitions.com (https://www.digitaltransitions.com/page/tech-camera-overview) list the SK 35/5.6 lens as "compatible" with <40MP backs and as "limited compatible" with 60MP backs.

So, I would be really glad to get some input from you knowleagable folks about what this means in reality. I routinely do 15-20mm shifts/rises with the Aptus 75S and the SK 35 without any color shift issues (and giving a damn about the slightly soft corners, as the therapist suggested). The LCC routines in Capture One 7.x work just great for me.

Would that change with the Credo 60 (which, I presume, has the same sensor as the IQ 160)? Would I get colr shift issues that can not be corrected in C1 with LCCs?

Also, why wouldn't the Credo 40/IQ 140 show the same issues then, since they both utilize 6 micron sensors? Does the 60 have microlenses and the 40 not (it used to be the other way round back in Kodak sensor times)?

What's more, I have the same question for the not-so-expensive SK 28/5.6 Super-Digitar XL, which would be a great 23HR replacement with the larger Credo 60 back...

Sorry for the long post, I really hope to get some valuable info from you, thanks in advance!

Gebhard

 

[Pemihan]

I'm going to tag along here..

I contemplating moving from a Leaf Aptus II 7 (same sensor as the 75S) to either IQ160 or IQ260 and have the exact same thoughts regarding the SK35XL (which I really like)

Peter

 

[stephengilbert]

Dan Lindberg uses both lenses with Leaf backs. You can find (beautiful) examples here -- http://www.getdpi.com/forum/medium-format-systems-digital-backs/29667-technical-camera-images.html -- and on his Facebook page.

 

[Guy Mancuso]

The 35xl worked perfectly fine with the IQ 160 which is the same sensor. I used the center filter as well. I can't remember how far I could shift but I don't recall any real issues with it. I sold it to get the Roadie 28.

 

[Guy Mancuso]

It just does not play nice with the 80mpx sensors otherwise it's a great lens for everything below it. I would try and go for the Credo 60 if you can stretch your budget.

 

[gebseng]

Thanks for the great responses! This is all very reassuring to me, I'd really like to continue with the SK 35.

Gebhard

 

[Guy Mancuso]

I would NOT sell it. I should have kept mine than bought the 23.

 

[GrahamWelland]

I use the 35XL APO-Digitar as my primary wide lens with the IQ160 and Aptus 65M, plus previously used it with the P40+ & IQ160 before. As mentioned above, it works well with the 60mp digital backs but you will obviously lose some shifting capability compared to what you have with your 75S. I typically can go to 8mm without concern for vignette (always corrected with LCC) and you can push it to 10mm depending upon the scene.

I always use the centre-filter with this lens to make LCC correction easier. You can shoot without it but it really pushes the LCC correction and you'll see noise and some loss of saturation due to the amount of correction applied.

 

[PeterL]

I'm using the SK 35XL with the IQ140 back, no center filter needed with this lens/back combination IMHO. LCC yes, but have no problems with corrections in C1. Shifts to 15mm no problems at all for critical application (conservative), can go to 18mm if not so critical (which I am, but for many applications no problems at all). I agree with Graham, the center filter may help with LCC, but you loose several stops. I prefer to use it without - at least for the IQ140/Credo 40 backs. One lens - completely overlooked by most people here, is the SK 24XL which works great on the IQ140/Credo 40 backs - just a thought . Sharper than the 35XL IMHO.

Cheers, -Peter

 

[gebseng]

I'm using the SK 35XL with the IQ140 back, no center filter needed with this lens/back combination IMHO. LCC yes, but have no problems with corrections in C1. Shifts to 15mm no problems at all for critical application (conservative), can go to 18mm if not so critical (which I am, but for many applications no problems at all). I agree with Graham, the center filter may help with LCC, but you loose several stops. I prefer to use it without - at least for the IQ140/Credo 40 backs. One lens - completely overlooked by most people here, is the SK 24XL which works great on the IQ140/Credo 40 backs - just a thought . Sharper than the 35XL IMHO.

Cheers, -Peter

Hi Peter, thanks for the valuable information! Especially the idea of using the 24 is great, I guess you could do about 5 or 6mm of shift with the 33x44mm sensor?

best,

Gebhard

 

[GrahamWelland]

The 24XL works really well with a 33x44 sensor. I shot it with my Aptus 65 and P40+ and it was a superb lens. The recessed lens board needs a little getting used to, plus it definitely needs the centre filter, but overall it's a great lens that unfortunately I sold when I got my IQ160 as it couldn't cover the sensor. However, with a crop sensor I had no image quality concerns whatsoever.

 

[GrahamWelland]

Btw, for a pure technical camera shooter I would definitely recommend looking at a 'crop' sensor. Whilst I don't regret going to a 60mp "full frame" sensor, for pure technical camera use I'd probably have been better served by my initial thoughts of going to the IQ140 vs the IQ160 I went with. Lens choice is basically unrestricted and you can use all of the Schneider wonderful glass which is both small and light plus doesn't require mortgaging your first born to buy unlike the Rodenstock retro focus glass.

 

[gebseng]

Btw, for a pure technical camera shooter I would definitely recommend looking at a 'crop' sensor. Whilst I don't regret going to a 60mp "full frame" sensor, for pure technical camera use I'd probably have been better served by my initial thoughts of going to the IQ140 vs the IQ160 I went with. Lens choice is basically unrestricted and you can use all of the Schneider wonderful glass which is both small and light plus doesn't require mortgaging your first born to buy unlike the wonderful Rodenstock retro focus glass.

very good points her, Graham! I should overcome my small sensor anxiety . Do you remember how much rise/fall you could do with the 24XL and the aptus 65?

geb

 

[GrahamWelland]

For technical cameras there really is no anxiety. What IS full frame anyway? It really doesn't matter a jot.

As regards movements with the 24XL. I really didn't ever try because it was so hyper wide anyway. I'm sure that the Alpa calculators can tell you. Probably only a few mm due to the image circle. 60mm ?? I'm sure someone will look it up and tell you.

 

[danlindberg]

Both the 28 & the 35 are excellent in combination with a Credo 60. You need centre filter and LCC but end result is what counts and overall iq is superb.
However, forget your 15-20mm shift that you are used to. That is stretching it too far.
The 35 can do 10mm and the 28 8mm on the long side. If you need more you are actually better off to cheat and keystone in post.

I agree that a Credo 40 'may' be better (and for once a cheaper option) in a tech outfit since you have virtually no lens restriction at all. As long as you are ok with the different field of view for each lens compared to a full size sensor. 40mp is plenty for just about anything anyway….

Since I have the combination you are thinking about, just let me know if there is any 'setting' you are interested in and I can shoot that and share!

 

[Guy Mancuso]

The one issue that should be mentioned with 40 mpx sensors is if you want to get wide than as the lenses get wider it also gets more expensive. One caveat is the 24xl is relatively cheap in cost so you can get one and be wide your also stuck with it in that sensor and can't upgrade with it. Good example of this is a 60 mpx sensor you can use the 35. With a 40 mpx sensor to get the same focal length you may need a expensive 28. Obviously the 60 mpx sensor is more expensive too. So you need to watch the balance of budget versus focal lengths. I had them all P40,P65,iq140 and IQ 160. If I bought today I would jump all over a IQ260. I also would need a special ski mask to visit the bank. LOL

 

[Guy Mancuso]

But truth be told as well I would not mind having the IQ 140 back either.

 

[danlindberg]

Thought I'd share a very recent image with the 28XL & Credo 60. Last Thursday I did a series of 8 images to the company that built this bridge and this particular one I maxed out a 8mm rise, but the top is still tacksharp without smear.
If you don't torture the 28XL, then it is absolutely FAB also with 60mp big gun.

 

[gebseng]

Both the 28 & the 35 are excellent in combination with a Credo 60. You need centre filter and LCC but end result is what counts and overall iq is superb.
However, forget your 15-20mm shift that you are used to. That is stretching it too far.
The 35 can do 10mm and the 28 8mm on the long side. If you need more you are actually better off to cheat and keystone in post.

I agree that a Credo 40 'may' be better (and for once a cheaper option) in a tech outfit since you have virtually no lens restriction at all. As long as you are ok with the different field of view for each lens compared to a full size sensor. 40mp is plenty for just about anything anyway….

Since I have the combination you are thinking about, just let me know if there is any 'setting' you are interested in and I can shoot that and share!

Thanks Dan, I really appreciate it! One question: the SK 28 and 35 seem really close in focal length, wouldn't it make more sense to have the 28 plus the 43mm?

Also thank you for your offer re shooting a certain setting! I will do a test with the SK35, my own aptus 65 and both the credo 40 and 60 on tuesday, hope that helps me decide.

geb

 

[gebseng]

The one issue that should be mentioned with 40 mpx sensors is if you want to get wide than as the lenses get wider it also gets more expensive. One caveat is the 24xl is relatively cheap in cost so you can get one and be wide your also stuck with it in that sensor and can't upgrade with it. Good example of this is a 60 mpx sensor you can use the 35. With a 40 mpx sensor to get the same focal length you may need a expensive 28. Obviously the 60 mpx sensor is more expensive too. So you need to watch the balance of budget versus focal lengths. I had them all P40,P65,iq140 and IQ 160. If I bought today I would jump all over a IQ260. I also would need a special ski mask to visit the bank. LOL

Thanks Guy! Yeah, I'm aware I'll be losing some wide angle FOV with the 44x33mm sensor. However, compared to my current 48x36 sensor that's only -10%. Right now, I substitute a 23 or 24mm by stitching with the SK35, which works great! And in a really desperate back-to-the-wall (literally!) situation when shooting architecture, I could even do some limited stitching with the credo 40 and the SK24.

Budget vs. focal length: very good point of course. When I started my reasoning about Credo 40 vs. 60, my first idea was to ditch the SK35 and either go for a 32HR with the credo 40 or a 40HR with the credo 60 (which both would be exact replacements considering the change in sensor size). But these Rodenstocks seem awfully expensive compared to the SK-s. Also, colleague photographers told me about more flare problems with the Rodenstocks compared to the SK-s. Another point is that I once had the Roddie 35HR as a loaner, and had some issues with barrel distortion near the outer end of the image circle, which is of course correctable if you jot down your shift/rise settings, but is a real no-go for high-volume commercial work. That's what made me think about keeping the SK35 in first place, and I'm really happy that seems to work out now!

geb