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Rudy Torres

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Question about so called "Digital" Large format lenses
« on: March 19, 2009, 05:34:35 pm »

Here's a question. Is the word "Digital" a bunch of hog-wash when it comes to large format lenses? As long as the lenses are designated APO, is that not enough?
I posted this question here since I am P25+ shooter but curious about Large format possibilities with my Sinar. Thanks guys.

- Rudy
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tho_mas

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Question about so called "Digital" Large format lenses
« Reply #1 on: March 19, 2009, 05:39:27 pm »

Quote from: Rudy Torres
Here's a question. Is the word "Digital" a bunch of hog-wash when it comes to large format lenses? As long as the lenses are designated APO, is that not enough?
I posted this question here since I am P25+ shooter but curious about Large format possibilities with my Sinar. Thanks guys.

- Rudy

http://www.schneideroptics.com/pdfs/photo/Digitar_Manual.pdf / p4:

Quote
Line Resolving Power
Resolution is measured by how many lines a lens can project side by side into 1 millimeter of
space with the lines still clearly distinguishable from each other. One black and one white line
make one line pair.

Capture Area and Resolving Power
The lens used with the small digital chip has to be able to project x times the lines onto the
same space then the large format lens! The higher the resolving power of the chip the more
crucial is the performance of the lens.

Chip Resolution
Sensors on chips are aligned in straight lines. The new chips with 6.8 micron sensor size have
approximately 148 ccd sensors per millimeter which equals apprx. 70 line pairs per millimeter.
Resolving Power in Comparison

Medium Format apprx. 40 to 60 line pairs per millimeter
Large Format apprx. 30 to 50 line pairs per millimeter
Digitar Lenses apprx. 90 to 200 line pairs per millimeter

For the P25 with 9microns the Rodenstock Apo Sironar Digital are fine as far as I know and saw from some images.
I wonder how well the Digitars will perform an a P65+ /  Leaf AFi II or other upcoming 6micron chips.
Resolving power of the Rodenstock HR goes up to 5microns if I remember correctly.
« Last Edit: March 19, 2009, 05:45:15 pm by tho_mas »
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Rudy Torres

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Question about so called "Digital" Large format lenses
« Reply #2 on: March 19, 2009, 06:39:25 pm »

Thanks for the pdf Tho_mas. But to be a little more realistic how many of you are still shooting with Hassy V systems not optimized for Digital. When I was shooting with an H20 on V System Zeis glass fringing happened all the time and for the exact reasons the PDF discusses. This fringing can be minimized in either the raw software and/or Photoshop. Also, once the commercial printing process (half-tone dots) deal with the image, fringing is pretty much a non-factor. So I ask again, what real difference does it make as long as the glass is designated as APO?

- Rudy
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tho_mas

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Question about so called "Digital" Large format lenses
« Reply #3 on: March 19, 2009, 07:07:05 pm »

Quote from: Rudy Torres
But to be a little more realistic (...)
Sole real world experience I can report of is I tryed a Rodenstock Apo Sironar Digital 4.5/45 (non HR!) on my P45 and it was soft. Shift was impossible on the P45. My Contax Distagon 2.8/45 was significantly better at all apertures. With the P25 the Rodenstock was good. Again the Schneider Digitar 47XL performs great on the P45 (stopped down) even with wide shift.
As to the conventional large format lenses I don't know...
« Last Edit: March 19, 2009, 07:07:41 pm by tho_mas »
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julius0377

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Question about so called "Digital" Large format lenses
« Reply #4 on: March 19, 2009, 07:34:38 pm »

My Schneider 38XL looks like it's shot through a layer of thin vaseline when compared to my 47XL digitar, the same goes for my 65SW nikon. There is a huge difference between the old film and new ditigally optimized lenses from Schneider/Rodenstock.
« Last Edit: March 19, 2009, 07:35:07 pm by julius0377 »
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CBarrett

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Question about so called "Digital" Large format lenses
« Reply #5 on: March 19, 2009, 08:01:53 pm »

I dunno guys, my circa 1960's Schneider 47mm Super Angulon makes some really sharp images on a P45.

I just used it about 7 hours ago... (Mind you, I'm still bidding on a 45mm Apo-Sironar Digital right now.... LOL)



100% 80mb Tif HERE
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klane

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Question about so called "Digital" Large format lenses
« Reply #6 on: March 19, 2009, 08:20:05 pm »

I cant say I tested older film lenses, but the schneider digitars I have are he best lens ive used on any camera system. What you have to consider is lens movement, and all the digitars ive used really hold up.
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brianc1959

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Question about so called "Digital" Large format lenses
« Reply #7 on: March 19, 2009, 10:57:06 pm »

"APO" is one of the most misused optical terms in photographic optics.  Aberration curves published by Rodenstock indicate that few, if any, of their APO designated lenses are actually apochromatic.  The HR 100/4 looks like it *might* be apochromatic (the sole exception), with a possible third color crossing in the NIR.
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jonstewart

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Question about so called "Digital" Large format lenses
« Reply #8 on: March 20, 2009, 08:58:49 am »

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« Last Edit: March 20, 2009, 08:59:22 am by jonstewart »
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Anders_HK

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Question about so called "Digital" Large format lenses
« Reply #9 on: March 23, 2009, 01:16:26 am »

Quote from: Rudy Torres
Here's a question. Is the word "Digital" a bunch of hog-wash when it comes to large format lenses? As long as the lenses are designated APO, is that not enough?
I posted this question here since I am P25+ shooter but curious about Large format possibilities with my Sinar. Thanks guys.

- Rudy


Hi Rudy,

I am having a custom made adapter be made for my Aptus 65 to go on my 4x5. Thus no real life experience yet to your question... however I have researched;-

1. Digital large format lenses are all medium format size, up to around 120mm image circle per what I recall. Thus they require more exact movements than 4x5, because you will simply use smaller capture area (film/sensor). In particular for wide angles where DOF (depth of focus) is very small it requires a technical digital camera. Both the lenses and such cameras are $$$. For very wide you may not need lens movements at all.

2. My personal aim is to use for landscapes and for stitching panorama. Thus I will use my digital back similar to film size; up to near 612 and sometimes 4x5. I personally believe this will work, but near future will prove me right or wrong.

3. Per email reply, per what I recall from Schneider, they said that an Aptus 65 is around borderline for their modern traditional lenses. I believe it will be ok with SHARP lenses for Aptus 65 which is a 44x33mm sensor and 28MP. For a 22MP 48x36mm sensor it should thus work fine, but no certainties.

Best will be to use sharp lenses, but there may be issues of diffraction at certain apertures. You will need a steady 4x5 camera also. Mine is a non folding Shen-Hao TFC45-IIB.

Regards
Anders
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