Centerfilter for Schneider 35mm XL Apo-Digitar

[Wayne Fox]

Actually, you will be giving up 2 stops of exposure, but increasing the dynamic range available to the LCC software as it has to do less work to correct brightness falloff. It will be primarily using up DR to adjust colour cast not density. This is why corrected files show less noise at the edges when the starting point is a file that was shot with a centre filter.

Not sure ... are we sort of saying the same thing? My point is that if you do not use a center filter, two stops of your sensors dynamic range will be lost in the fall off. If you do use a center filter, then you will have to increase exposure by two stops when you use it, but now the light falling on your sensor has been somewhat adjusted so you now can capture more of the dynamic range of the scene.

There are many occasions where not using a center filter can be very problematic, where the center of the image is already many stops brighter than the edges, such as sunsets etc. Without a center filter you may not be able to capture a full dynamic range adequately.

 

[GrahamWelland]

Seems to me that Wayne and Bryan are saying the same thing and agreeing with each other. :thumbs:

What I can add is that my 35 XL is probably arguably the sharpest lens I own and I LOVE it! I just bought the center filter myself too although with the P40+ crop it's not quite so critical. The infinity focus is somewhat different to my other lenses due to the fact that it doesn't hard stop at that point (I know that's so that you can adjust for the center vs edge focus) but I've grown to really really like this lens.

 

[Wayne Fox]

Actually, you will be giving up 2 stops of exposure, but increasing the dynamic range available to the LCC software as it has to do less work to correct brightness falloff. It will be primarily using up DR to adjust colour cast not density. This is why corrected files show less noise at the edges when the starting point is a file that was shot with a centre filter.

Seems to me that Wayne and Bryan are saying the same thing and agreeing with each other. :thumbs:

What I can add is that my 35 XL is probably arguably the sharpest lens I own and I LOVE it! I just bought the center filter myself too although with the P40+ crop it's not quite so critical. The infinity focus is somewhat different to my other lenses due to the fact that it doesn't hard stop at that point (I know that's so that you can adjust for the center vs edge focus) but I've grown to really really like this lens.

Unfortunately, I think it's a no go on the IQ180 ... very strange color casts, far more than I'm comfortable with. Problem is the color casts are all through the image, not limited to the corners. I"m all for LCC's, but at some point it's too much data manipulation and compensating too much for one thing means losing something else somewhere.

The lens was much better on the p65.

 

[Chris Barrett]

Adding fuel to the fire... My introduction to the IQ180 was 9 days ago at 5am. I didn't have a whole lot of time with it and I was trying to help lead a PODAS workshop at the time... so my testing was not in depth by any means. I threw the 35mm XL on my Rm3d, shifted it 15mm to the left and let it fly. The resulting LCC image was so frightening and that combined with reports here caused me to drop the IQ180 from my consideration without further exploration.

Now that I've got a few days off and am still haunted by the awesomeness of the IQ GUI, I've begun to re-explore that test. The P65+ and the P45+ before it have been so good to me that I feel I owe the brand a little more generosity.

Now, again, this was with the Schneider Apo-Digitar 35mm XL (which everyone says should NOT be used with the IQ 180), the camera is shifted 15mm (5mm more than anyone should really EVER shift this lens) and there was no Center Filter.

The two images are captures from the IQ180 (left) and then the P65+ (right). You'll notice I had the IQ180 ISO set to 100. Why? It was 5am and there was no coffee in sight!

I set the P65+ Light Falloff Correction to 56% because that's where I liked it esthetically (I typically back this correction off some to increase image depth). The IQ180 Light Falloff Correction is set to 73% to achieve corner readouts comparable to the P65+. 17% more correction... not too bad. It is obvious the IQ180 develops more fall off than the P65+ (which has more falloff than a P45+).

I would have absolutely no issues delivering either file to a client (if, ya know, it was a decent composition with better light). The over-shifted composition with the new WAT LCC on the IQ 180 at 73% correction has no issues to my eyes.

So how do I feel about everything now? I think I was too quick to dismiss the IQ180. It does provide just amazing detail, nicer clarity than the P65+ and allows for Big *** Prints. This hasn't convinced me to trade in my P65+ right away, but it has convinced me to do more real world testing. I especially want to see the difference with images that are inherently darker and see if corner noise is an issue.

I dig the little Schneider 35mm and I really love my 43mm and am not anxious to swap those out for the big, heavy and pricey Rodie HR's to solve falloff on the IQ180. But if I can integrate the new back into my current kit, I think I'll be a happy camper.


*All conclusions and opinions above are purely subjective and I have been known to be wrong about **** on occasion.

CB

 

[Wayne Fox]

Chris,

One issue is there is a very wide disparity between IQ180's and Lens Cast. I've been working with 2, and my dealer has sent me LCC's from a third, and they are all completely different. The first one wasn't even acceptable on the DF. Second one is better, but the dealer's is better than mine. With the 55LS on the DF, his shows no color change from top to bottom, just some expected density falloff, min shows a magenta/green shift from top to bottom. His LCC on the 35xls isn't great, but better than my current one. So if you are shooting a Tech camera, some will perform better than others.

I've heard from several sources that Phase is working on the issue, but seems it's probably more about the sensor and how it's stitched, so it may be just how things are going to be. I'd be curious to see the LCCs from those two shots.