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Author Topic: short report from 16shot sinar back  (Read 4198 times)
rainer_v
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« on: January 04, 2007, 02:49:41 PM »
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short report from my experience in my actual project, using here a lend  sinar 54h back.

i actually shoot pictures for a bookpublication for a german museum which will contain "Quilts of the Amish". these are 90 quilts from different textil textures and sized between 1mtr and 2,20mtr squares.

at first i tried my e75 back mounted on the contax 645, using the 80/2contax and the 100/3,5 hassy lense.
as expected the e75 showed in many textures  significant moiree.
not very nice and too much work to eliminate it in ps for 90 quilts.
after some tests i could find a very well working  workaround with caprock antialiasing filters ( to use in front of the lense ), i used the 5,4 filter from their filter serial ( named as f2,8 till f11 ).
the filters blur the colors, but they dont smear them as it easily happens with software moiree filters from capture or sinar in photoshop, but they blur the image in total.
so i shot one shot without the  aa filter, using it just for the luminance channel.  
afterwards a second shot which is blurred with the caprock filters, from that i used the color information in a layer. this works perfect for color moirees without visible loss of sharpness or color smearing.
for occassionally L moiree i could use also the blurred L info fron the color shot .
the files look good with 100% clean colors.
 
but what really blow me away was the 54h in 16 shot mode.
there are two ways to use the contax for 16shots :
one way is to make every of the shots with 2sec. self timer. in this mode the contax lift up the mirror and expose after 2 seconds. inconvenience here is that the sensor noise increases cause the sensor is activated for the two seconds "waiting" time also. if shot before the 16 shot a blackreference, than noise was not an issue with a total exp. time of 4seconds.
to avoid the increased noise floor i fixed later the mirror up with some tape ( i cant see a "mirror up mode " in the contax,- after every exposure the mirror is unlocked again ) and shot the 16shots in this way. the contax is not blocked by the taped mirror.
i used a very heavy tripoid and the 16 shots became tack sharp. i am surprised that the mf lenses resolve enough to make sharp images with 88mp- the results look so great......
had the feeling in direct compariosion from the e75 to the 54h as  if i compare my ricoh gr with my e75. just incredible. you see every structure in the textils and the clean colors allow very big magnifications. i did not expect so great difference....... and i think its great that they offer so different backs for different needs.
« Last Edit: January 04, 2007, 03:40:50 PM by rehnniar » Logged

rainer viertlböck
architecture photographer
munich / germany

www.tangential.de
Graham Mitchell
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« Reply #1 on: January 04, 2007, 07:08:18 PM »
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Graham Mitchell - www.graham-mitchell.com
David WM
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« Reply #2 on: January 04, 2007, 07:30:59 PM »
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Quote
after some tests i could find a very well working  workaround with caprock antialiasing filters ( to use in front of the lense )
[a href=\"index.php?act=findpost&pid=93713\"][{POST_SNAPBACK}][/a]

Thanks for sharing your experiences Rainer.
Do you have much experiecnce with these Caprock antialiasing filters generally?  For use with a 22, 33 or 39 MP back in situations where you can not do multi exposures how severe is the blurring, for example could it be comparred to a specific value of gausian blur?

David
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rainer_v
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« Reply #3 on: January 05, 2007, 01:11:19 AM »
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Quote
Thanks for sharing your experiences Rainer.
Do you have much experiecnce with these Caprock antialiasing filters generally?  For use with a 22, 33 or 39 MP back in situations where you can not do multi exposures how severe is the blurring, for example could it be comparred to a specific value of gausian blur?

David
[a href=\"index.php?act=findpost&pid=93776\"][{POST_SNAPBACK}][/a]

i will post some pics later .... have no time now.

its first time that i used the caprocks seriously.
in general it should work fine with one shots also.
the image looks soft if shot with the right filters, but you can use a lot of usm, its surprising how much detail is in the image blurred  and how much appear again with usm. clear that you cant do in one shot mode what i did with layering blurred color channels with unblurred luminance channel,
which seems to be the best way not loosing sharpness.
i dont think that the blurring can be compared with gausian blur, you need much less blur if the image is blurred before it is recorded, than afterwards in software.
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rainer viertlböck
architecture photographer
munich / germany

www.tangential.de
rainer_v
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« Reply #4 on: January 07, 2007, 03:58:58 AM »
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-mistake
« Last Edit: January 07, 2007, 04:21:40 AM by rehnniar » Logged

rainer viertlböck
architecture photographer
munich / germany

www.tangential.de
rainer_v
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« Reply #5 on: January 07, 2007, 04:08:52 AM »
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the motif wherefrom the crops are taken:
[attachment=1484:attachment]

the motif is a quilt which has a size of 210x210cm. the shot is taken from 7meter distance with a 100/3,5 hassy lense on the contax 645
the light was little bit different between the e75 shots and the 55h multishot. but i think its quite obvious to see what happens. the moiree is not so easy to see in the e75, but its there and destructs the colors enough to make the shot unusuable.
very interesting is to enlarge the shots more than 100%. the higher pixel quality of the 54h allows far better enlargements for big prints, aside the pure bigger file size.
also i am astonished that my old 100/3,5 hassy lense is able to deliver sharp files with 88mp size.
the crops are all sharpened in the same way with usm. the jpegs have quality 10 settings.




1. the e75 without any moiree treatment.
[attachment=1478:attachment]


2.  54h in 16 shot mode.
[attachment=1479:attachment]

3. e75 with caprock  filter 5,6
[attachment=1480:attachment]


4. e75 with caprock only applied for the color channels.
[attachment=1482:attachment]


5. e 75 with software demoirize.....
[attachment=1483:attachment]
« Last Edit: January 07, 2007, 04:20:33 AM by rehnniar » Logged

rainer viertlböck
architecture photographer
munich / germany

www.tangential.de
BJNY
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« Reply #6 on: January 07, 2007, 05:10:37 AM »
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rehnniar,
Thank you for the good info in this thread.  I've followed your posts about your customized Gottshalt at several forums, and have been looking forward to seeing it. Any chance you could post some pictures of your outfit?
Thank you,
Billy
« Last Edit: January 07, 2007, 07:47:54 AM by BJNY » Logged

Guillermo
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