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Site & Board Matters => About This Site => Topic started by: Bill VN on October 10, 2009, 03:01:21 pm

Title: Phase One Achromatic Plus Back Review
Post by: Bill VN on October 10, 2009, 03:01:21 pm
Didn't MegaVision build a black & white back before?
Title: Phase One Achromatic Plus Back Review
Post by: Wayne Fox on October 10, 2009, 03:33:03 pm
Several of the images from Claus don't seem to be showing up for me.

Title: Phase One Achromatic Plus Back Review
Post by: NikoJorj on October 10, 2009, 04:25:34 pm
Quote from: Wayne Fox
Several of the images from Claus don't seem to be showing up for me.
Ditto for me, there seems to be a quirk in the filename between what the page calls and the file, eg
http://www.luminous-landscape.com/images-99/Achromatic-portraits-100%-zoom.jpg
calls for
http://www.luminous-landscape.com/images-99/Achromatic-portraits-100%25-zoom.jpg

Edit : got it, it's because the sign percent "%" gets encoded with the code %25 in the URL, I'd guess links in the page have to be modified this way.

Just for curiosity's sake : can the sensitivity gain be assessed, at least with a mean?
How much of it would be offset by the TG1 filter?
Title: Phase One Achromatic Plus Back Review
Post by: Wayne Fox on October 10, 2009, 06:21:32 pm
Quote from: NikoJorj
Edit : got it, it's because the sign percent "%" gets encoded with the code %25 in the URL, I'd guess links in the page have to be modified this way.

Guessing that's right ... I believe the % symbol in a URL is interpreted to mean an ASCII hex equivalent, for example if you leave a space in a URL, it is replaced with %20, 20 being the ASCII hex value for space.

I've been stung by that before, using 100% in a filename.
Title: Phase One Achromatic Plus Back Review
Post by: michael on October 10, 2009, 08:05:34 pm
Sorry about that folks, the file name problem is now fixed.

Michael
Title: Phase One Achromatic Plus Back Review
Post by: DaveCurtis on October 10, 2009, 11:58:35 pm
I really enjoyed the review and the input from the three gents.

All I can say is wow! With no bayer, no AA and obviously a very good lens, it is amazing what can be produced.

After looking at my 1DS Mark3 images at 100%   ... well they kinda looks like mush in comparison.
Title: Phase One Achromatic Plus Back Review
Post by: knweiss on October 11, 2009, 07:48:51 am
Quote from: michael
Sorry about that folks, the file name problem is now fixed.
Michael, the title photo ("Hardy Lake #2") it's also a dead link (when you click it). Maybe the caption is wrong, too, because it shows a tree and there's a second image in this article called "Hardy Lake #2" which shows a lake...
Title: Phase One Achromatic Plus Back Review
Post by: michael on October 11, 2009, 08:46:19 am
Fixed again.

I worked on this article on two different machines over about a one month period and it seems that I neglected to synchronize the updates. Should be good now.

Michael
Title: Phase One Achromatic Plus Back Review
Post by: imagico on October 11, 2009, 02:54:22 pm
I think this is good news.

I am not too sure if this step by Phase One will encourage the usual suspects of camera/sensor makers 24x36 and below to also work on this kind of camera.  There are reasons why this would have advantage over an MFDB besides the price like:


But a lot of development could be necessary to get there for the camera makers and this would lead to expensive cameras compared to their normal Bayer counterparts.  Probably camera makers focused on high volume models are not much interested in such a small market and the Fuji UVIR models might also not sell too well (although AFAIK they still have a Bayer filter included).
Title: Phase One Achromatic Plus Back Review
Post by: Jack Flesher on October 12, 2009, 10:04:14 am
I'll just add redundant kudos.

Also, I noted a few "interesting" items in Claus' C1 screenshots  

,
Title: Phase One Achromatic Plus Back Review
Post by: Alan Goldhammer on October 12, 2009, 12:50:40 pm
In an article on this year's Nobel laueates for Physics, mention is made of a nice new camera for the Large Synoptic Survey Telescope that is worth holding out for.  Makes any of the Phase One products pale by comparison.  Guess I'll hold onto my Nikon D300 until this one (http://www.washingtonpost.com/wp-dyn/content/article/2009/10/11/AR2009101101675.html) is available (need to go to the end of the article for the specifications!!!).  
Title: Phase One Achromatic Plus Back Review
Post by: image66 on October 12, 2009, 04:04:10 pm
So, this is just a resolution test.

What about dynamic range?  What about a comparison of the Achromatic versus a desaturated P45+ or P65+ image?

Another aspect of this is the color sensitivity curves of the Achromatic back.  We have very limited control over the response curves of the sensor with standard B&W filters (orange, yellow, red, green...) and rely upon the sensor or film to have a little bit of non-linear character to provide a look which we are seeking. Which then begs the question:

If the sensor has been UV/IR filtered, which B&W film does it come closest to mimicking?  Tmax? TriX? Delta 100?  Acros?  And which version of the above films?

This is absolutely not a DR or contrast issue either.  This is as basic as it comes.  Is the sensor equally sensitive to green as it is to red as it is to blue as it is to yellow? If so, then we have a basic problem that is impossible to adjust for and correct in post-production.  Yes, you can filter the lens, but lens filters are broad-base and aggressive--blocking entire ranges of colors.  Films are nuanced to enhance certain colors and lower others. Films "see" differently--no two films are alike. Of course, an argument can be made that this is a whole new B&W "look"--it's own film characteristic, so to speak. If so, then we have to judge its merits on the overall pleasantness and usability of this "look". If it strays too far from tradition, then it will have a difficult time since it would be impossible to have a "Tri-X Look" for instance. To make up for this, we'd have to have a stack of CC gels on the lens or some famous nature photographer will come out with his own line of $2000 filters for achieving a better film "look". A whole new cottage industry will be born.  Where is Gary Fong when we need him?

This article addresses none of this.  It is a nice little adventure in dealing with one and only one subject:  Resolution.
Title: Phase One Achromatic Plus Back Review
Post by: Tyler Mallory on October 12, 2009, 06:48:14 pm
So how long 'til somebody rigs some RGB filters and turns this into an un-bayered 3-shot color back?
Title: Phase One Achromatic Plus Back Review
Post by: DarkPenguin on October 12, 2009, 07:00:36 pm
Quote from: Tyler Mallory
So how long 'til somebody rigs some RGB filters and turns this into an un-bayered 3-shot color back?

That's what I want to know.
Title: Phase One Achromatic Plus Back Review
Post by: fourfa on October 22, 2009, 03:38:20 pm
Removing the RGB filters ought to yield a significant improvement in ISO ability for visible-only photography.  Didn't see any mention in the article.  Maybe MFD photographers don't care much about handholdability and shutter speeds, but monochrome sensors for cameras like the M9 have been much talked about, and it would nice to see this quantified.
Title: Phase One Achromatic Plus Back Review
Post by: brianc1959 on October 22, 2009, 05:31:05 pm
Quote from: Bill VN
Didn't MegaVision build a black & white back before?

They did, and they still do:
http://www.mega-vision.com/cultural_heritage.html (http://www.mega-vision.com/cultural_heritage.html)
Title: Phase One Achromatic Plus Back Review
Post by: brianc1959 on October 22, 2009, 05:35:48 pm
Quote from: imagico
I think this is good news.


  • Lenses with wide spectral transmission like the Coastal Optics 60mm being available for these formats

The Coastal 60mm Apo actually works extremely well on a MFDB so long as you keep the focus setting between infinity and about 1:4.  For higher magnifications you will begin to get noticeable vignetting on 36mm x 48mm and larger sensors.  The 60mm was recently used in this configuration for an initial survey of some ancient documents in the near-UV.

Also, I am currently developing a new UV-VIS-IR lens specifically for MFDBs, and expect to be releasing it early next year.
Title: Phase One Achromatic Plus Back Review
Post by: brianc1959 on October 22, 2009, 05:39:09 pm
Quote from: Tyler Mallory
So how long 'til somebody rigs some RGB filters and turns this into an un-bayered 3-shot color back?

Megavision currently manufactures a USB-controlled filter wheel to do exactly that: (scroll to near the bottom of the page)

http://www.mega-vision.com/professional.html (http://www.mega-vision.com/professional.html)