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Author Topic: Damaged IR filter on older Leaf back  (Read 7938 times)

buzzski

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Damaged IR filter on older Leaf back
« on: December 12, 2006, 07:11:15 pm »

I wonder if anyone can help or advise me? I'm using a Leaf Cantare MF digital back with my old Hasselblad gear. I purchased it of ebay for not an awful lot of money and I'm well-pleased with the results. It has breathed new life in to my Blad gear and at 25 asa delivers surprisingly good images. However... the IR filter is scratched and I'm getting a bit tired of retouching all my images. The repair costs I've been quoted by Leaf exceed the purchased price of the back which I'm not too delighted at as you can imagine.

So, does anyone have any experience of removing tghe IR filter and shooting with an IR filter in front of the lens (because I've got an old Phase One one kicking around) Am I being naive or would that not be the same principle as the Phase One Lightphase working method? Afterall the Cantare uses the same Phillips chip...

Any advice would be very much appreciated - or indeed just your thoughts on this method.

Thanks, Craig
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ericstaud

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Damaged IR filter on older Leaf back
« Reply #1 on: December 12, 2006, 08:46:23 pm »

Filters behind the lens change your focus.  This is true of taping filters behind your 4x5 lens.  It is also true of the IR filter on digital cameras.

You would at least need a filter with the exact same thickness to replace the Leaf IR Filter.  It would also need to mount in the same position I would guess.

You need to clean the IR filter of dust pretty frequently with a MFDB.  With the filter removed the dust will settle directly on the sensor.  I don't know how you clean that.  Maybe you can't.

The IR filters are installed in special clean rooms with special anti-static equipment.  If you wanted to do anything yourself, you would likely need a clean room that is more sophisticated than wiping off you desk with a swiffer.

Good luck with the repair.  I hope the scratch was disclosed in the auction listing.

What is the "Phase One Lightpase working method"?
« Last Edit: December 13, 2006, 01:32:37 am by ericstaud »
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pprdigital

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Damaged IR filter on older Leaf back
« Reply #2 on: December 12, 2006, 10:58:38 pm »

Quote
I wonder if anyone can help or advise me? I'm using a Leaf Cantare MF digital back with my old Hasselblad gear. I purchased it of ebay for not an awful lot of money and I'm well-pleased with the results. It has breathed new life in to my Blad gear and at 25 asa delivers surprisingly good images. However... the IR filter is scratched and I'm getting a bit tired of retouching all my images. The repair costs I've been quoted by Leaf exceed the purchased price of the back which I'm not too delighted at as you can imagine.

So, does anyone have any experience of removing tghe IR filter and shooting with an IR filter in front of the lens (because I've got an old Phase One one kicking around) Am I being naive or would that not be the same principle as the Phase One Lightphase working method? Afterall the Cantare uses the same Phillips chip...

Any advice would be very much appreciated - or indeed just your thoughts on this method.

Thanks, Craig
[a href=\"index.php?act=findpost&pid=90158\"][{POST_SNAPBACK}][/a]

Craig:

Have you tried creating a new custom gain file? I've scratched IR filters before - well...one, and created a new custom shading reference (custom gain equivalent for a Sinarback) and darned if it didn't almost remove those scratches. And these weren't scratches, they were gouges. The story of how they appeared shall remain a closely held secret, except to purchasers of digital backs from PPR.  

Might be worth a try.

Steve Hendrix
PPR Digital
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Steve Hendrix
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buzzski

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Damaged IR filter on older Leaf back
« Reply #3 on: December 13, 2006, 05:44:21 pm »

Quote
Craig:

Have you tried creating a new custom gain file? I've scratched IR filters before - well...one, and created a new custom shading reference (custom gain equivalent for a Sinarback) and darned if it didn't almost remove those scratches. And these weren't scratches, they were gouges. The story of how they appeared shall remain a closely held secret, except to purchasers of digital backs from PPR.  

Might be worth a try.

Steve Hendrix
PPR Digital
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buzzski

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Damaged IR filter on older Leaf back
« Reply #4 on: December 13, 2006, 05:46:50 pm »

Thank you Steve, I will certainly give that a shot. I'm not exactly sure how to do this in the Leaf software - when you did it with your Sinarback was there some sort of reference file you shoot at or the like? I will investigate tomorrow and report back to you!

Thanks, Craig
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buzzski

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Damaged IR filter on older Leaf back
« Reply #5 on: December 13, 2006, 05:52:46 pm »

Thank you so much for your reply to my dilemma... I take on board your information and guidance. When I refered to the Phase One Lifgtphase method I was recalling back to early MF backs where an IR filter was attached in front of the lens as there wasn't one present on the back. I remember using one which I'd hired a few years back and I attached the filter very simply with a bit of blue-tack! Not very scientific, but it worked.

I was wondering in theory if I removed the IR filter off my back and then used an external IR filter in front of the lens if this would achieve the same purpose or if there would maybe then be a colour cast with the difference in glass etc...

Unfortunately the scratch was not disclosed on the listing, it was cheap though!

Thank you, Craig
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yaya

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Damaged IR filter on older Leaf back
« Reply #6 on: December 13, 2006, 07:19:30 pm »

Quote
Thank you Steve, I will certainly give that a shot. I'm not exactly sure how to do this in the Leaf software - when you did it with your Sinarback was there some sort of reference file you shoot at or the like? I will investigate tomorrow and report back to you!

Thanks, Craig
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Craig,

In Leaf Capture, go to Camera > Calibration > Gain and it'll open a dialog with instructions to follow.

You need to use a difuser filter (White plexi should be fine), place a light source in front of the lens and make sure the exposure is about 1-2 stops over.

I've attached the instructions from the manual for your convenience.

Yair

[span style=\'font-size:8pt;line-height:100%\']Yair Shahar | Regional Manager | Leaf EMEA |
mob: +44 77 8992 8199 | yair.shahar@kodak.com | www.leaf-photography.com
[/span]
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David WM

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Damaged IR filter on older Leaf back
« Reply #7 on: December 13, 2006, 08:30:57 pm »

I used to use a Leaf DCB2 with a scratch and made gain files to compensate. I needed to make gain files for every aperture at half stop intervals, but its impressive how much they can correct out.
David
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Dustbak

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Damaged IR filter on older Leaf back
« Reply #8 on: December 14, 2006, 09:10:01 am »

A custom gain file is one way to go. You mentioned you correct them I assume in PS, you can also make an action out of the correction you are constantly making.

The scratch is in a stationary place an will be exactly at the same place only depending on Landscap or Portrait.

The correction I assume is alway the same as well. This type of stuff is excellently handled by PS Actions.
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JeffR

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Damaged IR filter on older Leaf back
« Reply #9 on: December 17, 2006, 03:35:44 pm »

Hi Craig.
The IR filter on your Cantare can be easily removed, and replaced. I dont think you really need a ¨Clean Room¨ but a reasonably dust free one is advisable.
Use the bathroom after you have had a good hot shower and the steam has cleared.
The only problem you have is a you said in your post:- the cost of a new filter.

If you cannot get your problem fixed I am looking for a Hasselblad adapter for my Cantare, let me know.
Jeff
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buzzski

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Damaged IR filter on older Leaf back
« Reply #10 on: December 17, 2006, 04:09:13 pm »

Thank you one and all... I'm gonna go down the road of vreating a custom gain file for each lens and aperture and hope for the best. Ta, Craig
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