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Centerfilter for Schneider 35mm XL Apo-Digitar
- Thread starter timwier
- Start date
dougpeterson
Workshop Member
Sorry I missed the party but thomas has it all right.
Advantages of not using a CF:
- no loss of light
- no loss of optical quality (no additional glass)
- slightly lighter rig
Advantages of using a CF:
- you can even out the lens falloff with less chance for noise
- LCD preview in-camera is more accurate to final product
Any use of LCC constitutes "pushing" the file around. "Pushing" a file, by definition, increases noise; the more relevant question is "how much?".
Fortunately Phase/Leaf files exposed reasonably well at base ISO will take an enormous amount of abuse without showing problems. If, however, you're already using higher ISOs, or you already underexposed the file, or you are towards the limit of the maximum length of exposure for your back, or if you are really really anal about noise, then even a bit of pushing around will start to show meaningful noise.
The "party line" is that LCC can correct for "about 2 stops" of light-falloff. My statement mirrors this party line, with the addition of "but do your own testing".
Doug Peterson (e-mail Me)
__________________
Head of Technical Services, Capture Integration
Phase One Partner of the Year
Leaf, Leica, Cambo, Arca Swiss, Canon, Apple, Profoto, Broncolor, Eizo & More
National: 877.217.9870 *| *Cell: 740.707.2183
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Advantages of not using a CF:
- no loss of light
- no loss of optical quality (no additional glass)
- slightly lighter rig
Advantages of using a CF:
- you can even out the lens falloff with less chance for noise
- LCD preview in-camera is more accurate to final product
Any use of LCC constitutes "pushing" the file around. "Pushing" a file, by definition, increases noise; the more relevant question is "how much?".
Fortunately Phase/Leaf files exposed reasonably well at base ISO will take an enormous amount of abuse without showing problems. If, however, you're already using higher ISOs, or you already underexposed the file, or you are towards the limit of the maximum length of exposure for your back, or if you are really really anal about noise, then even a bit of pushing around will start to show meaningful noise.
The "party line" is that LCC can correct for "about 2 stops" of light-falloff. My statement mirrors this party line, with the addition of "but do your own testing".
Doug Peterson (e-mail Me)
__________________
Head of Technical Services, Capture Integration
Phase One Partner of the Year
Leaf, Leica, Cambo, Arca Swiss, Canon, Apple, Profoto, Broncolor, Eizo & More
National: 877.217.9870 *| *Cell: 740.707.2183
Newsletter | RSS Feed
Buy Capture One 6 at 10% off
Here is another consideration... there is debate if you should shoot new LCC plates on each location and use them just for that session. Others had good results with saved LCC corrections. I shoot them fresh each time if for no other reason than I have dust correction plates ready just in case picked up some crud during a lens change. If I do a rise/ fall or shift I always shoot a LCC plate even if is an often repeated amount.. say 5mm.
Archivue... have you had this problem? If the LCC doesn't work, then re-shoot or start a support case. If you are having Capture One problems you ma want to try a complete un-install. Maybe you are a Leaf back user and are having problems? Just trying to throw out some ideas....
What's the bug?
Have you created a case with Phase One?
I suggest you create a thread on the Phase One users website. You'll get a meaningful answer straight up.
Cheers,
GrahamWelland
Subscriber & Workshop Member
Apologies for the :OT:
Actually there is a thread (& open support case) over at Phase One regarding this LCC problem with Leaf Aptus 65/75 uncompressed/compressed file crashes & C1 Pro v6.1 & v6.1.1. It may apply to other Leaf backs too but these two I know about.
If this is your issue, the current solution until Phase One fix it is to revert to v6.01. or use Leaf Capture for now for LCCs.
Of course if this isnt the same issue then definitely open a support case. Although I don't have a fix for my problem yet, the Phase One folks have been very responsive and worked with me to help identify, validate and hopefully soon fix the issue. Bugs happen but how a company responds to them is just as important and so far Phase One have passed my initial sniff test on this.
:thumbup: for Phase One support. :thumbdown:
for the bug though.
Actually there is a thread (& open support case) over at Phase One regarding this LCC problem with Leaf Aptus 65/75 uncompressed/compressed file crashes & C1 Pro v6.1 & v6.1.1. It may apply to other Leaf backs too but these two I know about.
If this is your issue, the current solution until Phase One fix it is to revert to v6.01. or use Leaf Capture for now for LCCs.
Of course if this isnt the same issue then definitely open a support case. Although I don't have a fix for my problem yet, the Phase One folks have been very responsive and worked with me to help identify, validate and hopefully soon fix the issue. Bugs happen but how a company responds to them is just as important and so far Phase One have passed my initial sniff test on this.
:thumbup: for Phase One support. :thumbdown:
for the bug though.
stephengilbert
Active member
The Schneider IIF center filter threads are 72 x .75 mm.
Shashin
Well-known member
Doug:
Can you show the loss of quality when using a center filter? I am interested in seeing the impact.
The loss of quality is largely theoretical. In the real world, you will see no difference, unless you allow the two additional lens-to-air surfaces to get dirty.
The two CF filters I have (one Rodenstock and one Schneider)do cause a small amount of vignetting on the widest lenses.
The flare-suppression coatings are superb.
Note that using a CF does reduce the amount of lenscast slightly, so those having issues with Shcneiders on the 5.2micron sensors should be aware of this. The other big benefit is that the LCC software does not have to make as big a correction due to a lot of the falloff already being corrected. As such, there is less residual artifacting.
Phase are also working hard to improve the algorythm.
I happen to have the CF for this lens listed in the B&S at the moment -- as new for $200 shipped US. FWIW, it is the 2*G* that is correct for the 35 XL APO Digitar. As has been said, advantages are it eases the load on C1 for the LCC and most especially, eliminates the excess noise at the edges from said lifting. I have never noticed any loss of image quality from using one, though I suppose it's there in some minor form.
http://forum.getdpi.com/forum/showthread.php?t=28365
http://forum.getdpi.com/forum/showthread.php?t=28365
Just to avoid any confusion, there are two CFs available for the 35mmXL A/D:
Centre Filter IIf 52/72
4x/2 stop Centre Filter that screws into the 52mm filter thread on the front of the 35mm XL lens
Centre Filter IIg 67/72
4x/2 stop Centre Filter that screws into the 67mm filter thread on the front of the panel in pre mounted 35mm XL lenses
The IIf is the most common one - I had it for the 35mm XL A/D in Cambo mount. Definitely needed with the 35mm XL A/D. Not sure I've ever seen a 35mm XL A/D with a 67mm front thread - maybe an Alpa variant or similar?
Centre Filter IIf 52/72
4x/2 stop Centre Filter that screws into the 52mm filter thread on the front of the 35mm XL lens
Centre Filter IIg 67/72
4x/2 stop Centre Filter that screws into the 67mm filter thread on the front of the panel in pre mounted 35mm XL lenses
The IIf is the most common one - I had it for the 35mm XL A/D in Cambo mount. Definitely needed with the 35mm XL A/D. Not sure I've ever seen a 35mm XL A/D with a 67mm front thread - maybe an Alpa variant or similar?
GrahamWelland
Subscriber & Workshop Member
My Alpa mount Schneider 35 XL Apo-Digitar is 52mm and takes the IIf. The Apo-Switar variant from Alpa (same optics) has the 72mm filter thread and requires a IIa filter.
Wayne Fox
Workshop Member
To me the real issue of whether to use a CF or not is if you want to give up 2 stops or so of your sensors dynamic range.
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.
Christopher
Active member
True, but you still loose 2 stops in exposure time. So at dawn it can be a problem, if you need 90 seconds instead of 30.