Luminous Landscape Forum

Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: narikin on October 07, 2006, 11:37:22 am

Title: Alpa TC21 and Phase MF back?
Post by: narikin on October 07, 2006, 11:37:22 am
anyone using this combo and can give their advice?
I apprecaite that the Alpa works slightly better with Leaf backs (no wake up issues)
is that a real problem? does the Kapture Group cable release solve it?

need some user advice to help me decide. thanks.
Title: Alpa TC21 and Phase MF back?
Post by: markowich on October 07, 2006, 12:16:23 pm
the wake-up issue with phaseone backs is an annoyance, but in my view much preferable to the
centerfold problem of leaf. other than that, alpa pairs wonderfully with digibacks and with the schneider digitars.
peter
Title: Alpa TC21 and Phase MF back?
Post by: narikin on October 07, 2006, 12:34:18 pm
thanks, so is there a handgrip that integrates the KG/Phase cable release into it, like the Linhof anatomical does?  
the tiny finger grips on the TC21 look good, but I cant see how you effectively hold the cable release at the same time.

also are self cocking/ electronic shutters available so you dont need to remember that?
Title: Alpa TC21 and Phase MF back?
Post by: markowich on October 07, 2006, 12:45:14 pm
i  always used the normal (tiny ) handgrip and mechanical shutters. not tooooooooo comfortable but perfectly doable. i hear from alpa/phase that they are developing a new wake up cable though.
peter
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 07, 2006, 05:13:36 pm
The Alpa system is really a wide angle system.  This is not entirelly clear looking at the camera.  The viewfinder is fisheye (very wide view with curved lines) with masks to crop the image for each particular lens.  The 24mm mask shows most of the  area of the viewfinder.  My 60mm mask looks very small through the viewfinder.  Also, the nature of a range finder on which you estimate focus lends itself more to wide ange lenses with greater depth of field.  

I have used the Phase one on a Cambo wide, which is exactly the same principle as an Alpa ( just a whole lot uglier   ).  You simply press the cable release half way.  Wait for a fraction of a second while the lights on the back will begin blinking. Then you press the shutter the rest of the way.  You will use the cable release all the time with the Phase back.  You will need to anticipate pictures futher in advance to have time to wake up the back.

With the leaf you can use any cable release attached to the lens, or you can press the shutter directly with the nifty release Alpa provides.  If you want to do street, or handheld photography the Leaf is definitely the way to go.  The only special connection is a small sync cable from the back to the flash sync on the lens (don't leave home without that cable).

The centerfold issue on Leaf is no different than the LCC issue with the Phase One backs.  Leaf provides a usefull solution to remove the centerfold just like Phase One has a way to remove LCC.  Both companies have you shooting a white plastic card between shots.  Leaf has promised to provide me with an Aptus 75 which does not suffer from these issues.  When that arrives  I will not be shooting the white plastic card.  I will also not be waiting for the back to "wake up" before captures.  The centerfold effect comes from using non-retrofocus lenses which sit very close to the sensor, and as such, mostly effects architectural or landscape photographers.

It may be possible with the 12TC to shoot a few calibration images and keep them at home for either Phase One or Leaf.  Because you will not be using shifts on the TC you may only need a few images for each lens at different F-Stops.

The Leaf Custom Gain Adjuster which fixes the centerfold issue also can remove Lens falloff the same way you would use a centerfilter.  You dial in the ammount as a percentage from 0% - 100%.  Phase one does not do this.

The Custom Gain adjuster also creates a new MOS file with the falloff and centerfold fixed.  This allows you to take the corrected RAW file to ACR or Lightroom or RAW Developer....

If you have LCC issues with Phase One I believe (don't quote me) that you would be forced to use the C1 Pro software to process the RAW file.

-Eric
Title: Alpa TC21 and Phase MF back?
Post by: markowich on October 07, 2006, 06:39:59 pm
Quote
The centerfold effect comes from using non-retrofocus lenses which sit very close to the sensor, and as such, mostly effects architectural or landscape photographers.

[a href=\"index.php?act=findpost&pid=79471\"][{POST_SNAPBACK}][/a]

this is not true. the centerfold effect is a consequence of sensor design/readout, it is certainly much more visible with wide angle non-retrofocus lenses. i shall be very happy to receive an aptus 75 without the centerfold effect on alpa/shneider digitar 24mm but i doubt that this will happen without a serious sensor redesign by dalsa (so my chip cowboys tell me).
peter
Title: Alpa TC21 and Phase MF back?
Post by: vgogolak on October 07, 2006, 07:34:05 pm
The centerfold issue on Leaf is no different than the LCC issue with the Phase One backs.  Leaf provides a usefull solution to remove the centerfold just like Phase One has a way to remove LCC.  Both companies have you shooting a white plastic card between shots.  Leaf has promised to provide me with an Aptus 75 which does not suffer from these issues.  When that arrives  I will not be shooting the white plastic card.  I will also not be waiting for the back to "wake up" before captures.  The centerfold effect comes from using non-retrofocus lenses which sit very close to the sensor, and as such, mostly effects architectural or landscape photographers.


I recently tried the P45 with my contax 645 35mm (pretty wide, against pale sky and had no color cast issues at all)
maybe a Schneider 24 is a different story but 35mm is quite wide on MF

Victor
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 07, 2006, 11:08:01 pm
"I recently tried the P45 with my contax 645 35mm (pretty wide, against pale sky and had no color cast issues at all)
maybe a Schneider 24 is a different story but 35mm is quite wide on MF

Victor"

Hi Victor,

It is important to understand that all the people on the forum having trouble with the centerfold effect are people using Non-retrofocus lenses like the schneider digitars on cameras like the Alpa 12SWA, Cambo Wide DS, or Horseman SW-D.  This is not an issue for the retrofocus crowd.  The 35mm lens on your Contax is an entireley diffferent lens design than the 35mm digitar.  The rear element on my 35 digitar sits about 25mm from the sensor.

-Eric
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 07, 2006, 11:15:19 pm
"this is not true. the centerfold effect is a consequence of sensor design/readout, it is certainly much more visible with wide angle non-retrofocus lenses. i shall be very happy to receive an aptus 75 without the centerfold effect on alpa/shneider digitar 24mm but i doubt that this will happen without a serious sensor redesign by dalsa (so my chip cowboys tell me).
peter"

I don't get the point of disagreeing with me Peter.  "it is certainly much more visible with wide angle non-retrofocus lenses".  Are you implying that there are people with Retrofocus lenses having this issue?  Can you point me to the threads?  As I understand it, this is strictly limited to the non-retrofocus lenses.

As for your second point... I hope it is not true that the redesign will have to occur.  But this is no different than it is with Phase One files.  The rainbow colors of a Phase One image on my Alpa are no more usable uncorrected than the Leaf images with a centerfold line.

-Eric
Title: Alpa TC21 and Phase MF back?
Post by: zzzone on October 08, 2006, 03:43:42 am
Can anyone advise whether the centrefold or alternatively the lens cast issue are problems with the Aptus 22 or the P25 backs i.e. those backs with the large sensor sites?

I am in the process of purchasing a MFDB probably to go on a Cambo WDS with the 24 and 35 schneider lens.  So far I have come to the conclusion that the price differential between the A22 and A75 or the P25 and P45 is insufficient to persuade me to go for the lower resolution back.  I had concluded that I would just bite the bullet and go for it, the A75 or P45 being more futureproof for me.

But to buy into these problems described on this excellent forum I would be very disappointed.  The truth of the matter is that my clients would be more than happy with the output from the lower res solution and should either the A22 or P25 not have their respective problem then I would be much happier too!!  The purchase would actually be their respective replacments the A54s or alternatively the P25+

Steve
Title: Alpa TC21 and Phase MF back?
Post by: marcwilson on October 08, 2006, 05:07:43 am
Quote
Can anyone advise whether the centrefold or alternatively the lens cast issue are problems with the Aptus 22 or the P25 backs i.e. those backs with the large sensor sites?


Steve
[a href=\"index.php?act=findpost&pid=79513\"][{POST_SNAPBACK}][/a]


also do these issues affect aptus 17 backs.
It would be interesting to know..not because that would turn me away from leaf..phasse have their own isues also..but just to be prepared.

Marc
Title: Alpa TC21 and Phase MF back?
Post by: yaya on October 08, 2006, 05:25:02 am
Quote
also do these issues affect aptus 17 backs.
It would be interesting to know..not because that would turn me away from leaf..phasse have their own isues also..but just to be prepared.

Marc
[a href=\"index.php?act=findpost&pid=79516\"][{POST_SNAPBACK}][/a]

The A17 and A22, using larger pixels and a slightly different sensor design, do not appear to have any centerfold issues and will very rarely show any colour casts with wide-angle, non-retrofocus lenses.

Yair
Title: Alpa TC21 and Phase MF back?
Post by: zzzone on October 08, 2006, 05:38:17 am
Quote
The A17 and A22, using larger pixels and a slightly different sensor design, do not appear to have any centerfold issues and will very rarely show any colour casts with wide-angle, non-retrofocus lenses.

Yair
[a href=\"index.php?act=findpost&pid=79518\"][{POST_SNAPBACK}][/a]


Hi Yair

Presumably I am correct in assuming that this will be the case with the forthcoming A54s back as well?

Steve
Title: Alpa TC21 and Phase MF back?
Post by: markowich on October 08, 2006, 05:54:46 am
Quote
"this is not true. the centerfold effect is a consequence of sensor design/readout, it is certainly much more visible with wide angle non-retrofocus lenses. i shall be very happy to receive an aptus 75 without the centerfold effect on alpa/shneider digitar 24mm but i doubt that this will happen without a serious sensor redesign by dalsa (so my chip cowboys tell me).
peter"

I don't get the point of disagreeing with me Peter.  "it is certainly much more visible with wide angle non-retrofocus lenses".  Are you implying that there are people with Retrofocus lenses having this issue?  Can you point me to the threads?  As I understand it, this is strictly limited to the non-retrofocus lenses.

As for your second point... I hope it is not true that the redesign will have to occur.  But this is no different than it is with Phase One files.  The rainbow colors of a Phase One image on my Alpa are no more usable uncorrected than the Leaf images with a centerfold line.

-Eric
[a href=\"index.php?act=findpost&pid=79505\"][{POST_SNAPBACK}][/a]

hi eric,
sorry for the confusion, but it was merely a 'philosophical-scientific' issue, i wanted to make the point that the current chip design is at fault. actually, i am not sure whether the centerline effect may also-conceptually- occur in retrofocus lenses, wider than, say 35mm (which to my knowledge are not on the market yet). in any case, my contacts in the chip design community are pretty firm on the necessity for redesigning the salsa chip. unless, of course, a software fix is acceptable. yair just sent me the leaf custom gain adjuster, i shall try it out.
p
Title: Alpa TC21 and Phase MF back?
Post by: marcwilson on October 08, 2006, 06:02:24 am
Quote
The A17 and A22, using larger pixels and a slightly different sensor design, do not appear to have any centerfold issues and will very rarely show any colour casts with wide-angle, non-retrofocus lenses.

Yair
[a href=\"index.php?act=findpost&pid=79518\"][{POST_SNAPBACK}][/a]


Thanks yair,
That is what I assumed but good to make sure. It is the lack of colour shift etc that is making me lean towards the leaf backs over the phase ones.

Marc
Title: Alpa TC21 and Phase MF back?
Post by: narikin on October 08, 2006, 10:40:45 am
Quote
i  always used the normal (tiny ) handgrip and mechanical shutters. not tooooooooo comfortable but perfectly doable. i hear from alpa/phase that they are developing a new wake up cable though.
peter
[a href=\"index.php?act=findpost&pid=79441\"][{POST_SNAPBACK}][/a]
thanks for the info (and for staying on topic).
any more info on that cable??

I appreciate that the TC21 is designed really as a wide angle camera, but am surprised they dont make a 'normal' finder available for when you are using a 60-90mm lens, or thereabouts. It's a sweet small package otherwise, and I covet it for that.

As an aside I have to say there is a lot of nonsense written about Phase and LCC issues, it really is only in some extreme lens-camera cases that you see this, apparently. I say 'apparently' as I've not seen it once in 8 months of P45 ownership. (I dont do ultrawide architecture photos, but just about everything else, macro to portrait to landscape). It seems there is some rather petty minded Phase-bashing going on by Leaf owners here, that is not worthy of a pro forum discussion.  The P45 is a great product, a mature and stable workhorse delivering excellent results, and about to get even better with the + version. Mine is on order already.
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 08, 2006, 12:35:08 pm
Hi Narikin,

"As an aside I have to say there is a lot of nonsense written about Phase and LCC issues, it really is only in some extreme lens-camera cases that you see this, apparently."

I have used the P25 and H25 extensively with the 24, 35, and 60mm digitars.  These are not extreme lenses.  I use them every day, as does most every other architectural photographer who shoots medium format digital.  I see heavy LC on EVERY picture.  My experience is about 3 years of Phase One use several times a month.  I have used the Leaf extensively for the past year in addition to the Phase One.  What experience do you have with these backs and the non-retrofocus lenses that lead you to post the above statement?  My experience with these products has been very different than yours.

Regards,

Eric

I also don't see how a discussion of lens cast and centerfold is off the topic of:  "Alpa TC21 and Phase MF back?"  Often people don't ask the pertinent questions about a product they are considering.  The LCC and Centerfold topic will consume much more of your time with an Alpa and MFDB combo than the cable release issues.
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 08, 2006, 04:57:02 pm
Quote
thanks for the info (and for staying on topic).
any more info on that cable??

I appreciate that the TC21 is designed really as a wide angle camera, but am surprised they dont make a 'normal' finder available for when you are using a 60-90mm lens, or thereabouts. It's a sweet small package otherwise, and I covet it for that.

As an aside I have to say there is a lot of nonsense written about Phase and LCC issues, it really is only in some extreme lens-camera cases that you see this, apparently. I say 'apparently' as I've not seen it once in 8 months of P45 ownership. (I dont do ultrawide architecture photos, but just about everything else, macro to portrait to landscape). It seems there is some rather petty minded Phase-bashing going on by Leaf owners here, that is not worthy of a pro forum discussion.  The P45 is a great product, a mature and stable workhorse delivering excellent results, and about to get even better with the + version. Mine is on order already.
[a href=\"index.php?act=findpost&pid=79542\"][{POST_SNAPBACK}][/a]

my 2 cents: I use alpa and phase one backs with a few of alpa's wide angle lenses in addition to using a hassy system h2 with their wide-angle lens and other hassy lenses and Never had a LCC issue. I couldn't agree more, the phase backs are workhorses. they're very stable, reliable products. . .in all weather and environmental conditions. coupled with their great software product, C1 pro, IMHO, it's the digital back of choice. i also like the fact that phase are upgrading and improving (significantly) their already existing "p" product line to the +. . . .this is a great move by phase. mine are on order too!

BTW: alpa now has a wakeup/handgrip to take the place of the kapture group cable.

pp
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 08, 2006, 05:29:43 pm
I was told this is normal performance for the Phase One backs regarding LCC with the super wide lenses....  the 2nd one is corrected (obviously)

[attachment=1021:attachment]

[attachment=1022:attachment]
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 08, 2006, 06:26:18 pm
Quote
I was told this is normal performance for the Phase One backs regarding LCC with the super wide lenses....  the 2nd one is corrected (obviously)

[a href=\"index.php?act=findpost&pid=79580\"][{POST_SNAPBACK}][/a]

the important phrase in your statement is "normal performance". i can tell you that this is NOT normal performance for me. and it seems as though it's not normal performance for many of us phase people. i see that you have corrected it beautifully (i will assume in c1 pro). (with tongue firmly planted in cheek): can you correct the leaf centerfold problem as easily?

pp
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 08, 2006, 07:34:20 pm
"(with tongue firmly planted in cheek): can you correct the leaf centerfold problem as easily?"

Yes the color in those samples is corrected using the LCC in C1 Pro.  It is just as easy to correct the centerfold line (in my experience).  The concept is functionally identical from the users standpoint.  Shoot a white plexi card and let the software correct out the color casts and centerfold.  One main difference is that Leaf uses a stand alone application and C1 Pro has the utility built in.  Another difference is that the Leaf utility allows for removal or Lens falloff (which I ussually leave intact).  With C1 pro I would correct files later, in photoshop.

-Eric
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 08, 2006, 09:21:18 pm
Quote
"(with tongue firmly planted in cheek): can you correct the leaf centerfold problem as easily?"

Yes the color in those samples is corrected using the LCC in C1 Pro.  It is just as easy to correct the centerfold line (in my experience).  The concept is functionally identical from the users standpoint.  Shoot a white plexi card and let the software correct out the color casts and centerfold.  One main difference is that Leaf uses a stand alone application and C1 Pro has the utility built in.  Another difference is that the Leaf utility allows for removal or Lens falloff (which I ussually leave intact).  With C1 pro I would correct files later, in photoshop.

-Eric
[a href=\"index.php?act=findpost&pid=79596\"][{POST_SNAPBACK}][/a]


yes. i'm quite aware of the lcc facility in c1 pro. oh. . . .so let me get this straight: the lcc situation for phase one (if there really is a "situation" for some) can be handled very easily. i'm not a leaf owner, but if i were confronted with the centerfold problem i would have a very sick feeling in the pit of my stomach because i don't think it's easily handled as in a lcc situation because there is a very clear demarcation - a line - whereas with lc, it's a gradation which lends itself much more readily to a recalibration using software. understandably, leaf are not saying publically that this is the official way to handle centerfold issues.

an aside point which i think is worth mentioning to potential digital back buyers is that phase one in addition to having phone and email support, has a support forum where all their "dirty laundry" are aired in the open for everyone to view and evaluate.

pp
Title: Alpa TC21 and Phase MF back?
Post by: eronald on October 08, 2006, 09:44:03 pm
Quote
an aside point which i think is worth mentioning to potential digital back buyers is that phase one in addition to having phone and email support, has a support forum where all their "dirty laundry" are aired in the open for everyone to view and evaluate.

pp
[a href=\"index.php?act=findpost&pid=79609\"][{POST_SNAPBACK}][/a]

Yes, the public Phase forum is a good idea. Confidence building.

Edmund
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 08, 2006, 11:42:35 pm
"i don't think it's easily handled as in a lcc situation because there is a very clear demarcation - a line"

In my experience, the line is very easy to deal with.  The line occurs at an exact location.  So the picture of your subject and the picture of the Plexi card have the line in EXACTLY the same place.  The utility is called the Custom Gain Adjuster.  It uses the Plexi shot as sort of a mask which equalizes the sensor reaction to light coming from that particular lens at the settings you used to make your innitial image.  It is a gain adjustment, and as such, can also remove lens fall-off if chosen by the user.
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 09, 2006, 12:54:21 am
Quote
"i don't think it's easily handled as in a lcc situation because there is a very clear demarcation - a line"

In my experience, the line is very easy to deal with.  The line occurs at an exact location.  So the picture of your subject and the picture of the Plexi card have the line in EXACTLY the same place.  The utility is called the Custom Gain Adjuster.  It uses the Plexi shot as sort of a mask which equalizes the sensor reaction to light coming from that particular lens at the settings you used to make your innitial image.  It is a gain adjustment, and as such, can also remove lens fall-off if chosen by the user.
[a href=\"index.php?act=findpost&pid=79619\"][{POST_SNAPBACK}][/a]

hmmmm. . . .since this line is very easily dealt with, all the leaf owners who experience this centerfold problem should quit complaining. . . .at least until leaf replace the defective sensors
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 09, 2006, 02:44:06 am
"hmmmm. . . .since this line is very easily dealt with, all the leaf owners who experience this centerfold problem should quit complaining. . . .at least until leaf replace the defective sensors"

Except that one of the main selling points of the Leaf back was not having to shoot a plastic card with every shot.  For me personally it adds another 30-60 minutes to every shoot day to shoot the extra images and then apply those corrections back at the computer.

I shot an annual report with a P25 earlier this year mostly untethered.  It took alot of time to create an LCC for each setup and apply that to all the images from that setup at the end of the day.  If I wanted to try an alternate composition by shifting up 3mm, I would have to shoot another LCC shot for that bracket.  I have used a few Phase backs and have always seen the LCC issue with these lenses (sometimes it may only be a corner of a white room going 2 points magenta).  It is a known and accepted part of using the Kodak sensor.  Like dealing with reciprocity from the film days it is just something that Phase One users accept as part of the workflow.

The primary reason I now own an Aptus 75 is to avoid the Plastic card.  I was willing to sacrafice the superior workflow of C1 pro, and the ability to shoot long exposures so that I could just walk out my door with my Alpa and Aptus 75 around my neck and shoot pictures knowing that the files would not need a LCC or gain adjustment.

Of course I have to appologize to narikin for officially hijacking this thread.  I just felt that if Leaf does solve this problem, then the Aptus 75 will be a back that is better suited to a handheld camera like the Alpa 12TC with the wide digitars and HR's than the P45.  Put the Alpa on a tripod and it may be a different story.

Also Narakin,  There is a universal shoe that Alpa sells...

http://www.alpa.ch/en/products/pictures/_l...tive0-25-25.jpg (http://www.alpa.ch/en/products/pictures/_l/Negative0-25-25.jpg)

This would allow you to use viewfinders from other cameras like a Cambo Wide, Horseman, Leica, Blah, Blah, Blah.  You may find something more suitable for the normal to long lenses.  Jeff at Fotocare is my Alpa dealer and he has been very helpful with questions like this.  I'm sure Jeff at Badger is very good too.
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 09, 2006, 12:30:14 pm
Quote
"hmmmm. . . .since this line is very easily dealt with, all the leaf owners who experience this centerfold problem should quit complaining. . . .at least until leaf replace the defective sensors"

Except that one of the main selling points of the Leaf back was not having to shoot a plastic card with every shot.  For me personally it adds another 30-60 minutes to every shoot day to shoot the extra images and then apply those corrections back at the computer.

I shot an annual report with a P25 earlier this year mostly untethered.  It took alot of time to create an LCC for each setup and apply that to all the images from that setup at the end of the day.  If I wanted to try an alternate composition by shifting up 3mm, I would have to shoot another LCC shot for that bracket.  I have used a few Phase backs and have always seen the LCC issue with these lenses (sometimes it may only be a corner of a white room going 2 points magenta).  It is a known and accepted part of using the Kodak sensor.  Like dealing with reciprocity from the film days it is just something that Phase One users accept as part of the workflow.

The primary reason I now own an Aptus 75 is to avoid the Plastic card.  I was willing to sacrafice the superior workflow of C1 pro, and the ability to shoot long exposures so that I could just walk out my door with my Alpa and Aptus 75 around my neck and shoot pictures knowing that the files would not need a LCC or gain adjustment.

Of course I have to appologize to narikin for officially hijacking this thread.  I just felt that if Leaf does solve this problem, then the Aptus 75 will be a back that is better suited to a handheld camera like the Alpa 12TC with the wide digitars and HR's than the P45.  Put the Alpa on a tripod and it may be a different story.

Also Narakin,  There is a universal shoe that Alpa sells...

http://www.alpa.ch/en/products/pictures/_l...tive0-25-25.jpg (http://www.alpa.ch/en/products/pictures/_l/Negative0-25-25.jpg)

This would allow you to use viewfinders from other cameras like a Cambo Wide, Horseman, Leica, Blah, Blah, Blah.  You may find something more suitable for the normal to long lenses.  Jeff at Fotocare is my Alpa dealer and he has been very helpful with questions like this.  I'm sure Jeff at Badger is very good too.
[a href=\"index.php?act=findpost&pid=79626\"][{POST_SNAPBACK}][/a]


after taking over 50,000 images with my phase backs, i've never had to use the calibration card with my phase digital backs in the studio on a neutral gray background or out of the studio. i've never had a color cast issue - ever. Never with my alpa or h2.

pp
Title: Alpa TC21 and Phase MF back?
Post by: andrewparker on October 10, 2006, 05:43:57 am
Quote
my 2 cents: I use alpa and phase one backs with a few of alpa's wide angle lenses

Since Alpa don't make lenses, as far as I know, can we assume that you are using Schneider or Rodenstock non-retrofocus wide angles on an Alpa view camera,
and not having any colour cast problems with Phase backs?

I am curious because this is such a well-known technical isssue that even Phase dealers are open about in person, and you seem to be saying that you haven't had it yourself.

I may be missing something- can you clarify?

Andrew Parker
Title: Alpa TC21 and Phase MF back?
Post by: vgogolak on October 10, 2006, 10:17:30 pm
Quote
I was told this is normal performance for the Phase One backs regarding LCC with the super wide lenses....  the 2nd one is corrected (obviously)

[attachment=1021:attachment]

[attachment=1022:attachment]
[a href=\"index.php?act=findpost&pid=79580\"][{POST_SNAPBACK}][/a]
Dear Eric

Yes the non-retro lenses certainly have bigger angle of incidence proble. However, these images look more like white balance. I can't believe LCC is causing the shift, in fact it is right on boresight.
also LCC is more in warmer colors.
I thing there could be some color shift but this looks like WB issue mostly

Victor
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 10, 2006, 12:41:48 pm
Quote
Since Alpa don't make lenses, as far as I know, can we assume that you are using Schneider or Rodenstock non-retrofocus wide angles on an Alpa view camera,
and not having any colour cast problems with Phase backs?

I am curious because this is such a well-known technical isssue that even Phase dealers are open about in person, and you seem to be saying that you haven't had it yourself.

I may be missing something- can you clarify?

Andrew Parker
[a href=\"index.php?act=findpost&pid=79765\"][{POST_SNAPBACK}][/a]

yes of course. . .i use schneider wide angles on the alpa. and yes i have no lens cast problems. i am very careful to do white balance calibration for every condition. the only "well-known" technical issue for phase one regarding lens cast is if you use wide angle lenses on a horseman digiflex ii, or hassy flexbody or 905swc or other large format cameras with different tilt or swing settings. the lens cast problem is most visible on a neutral grey background and appears as a very green cast in one corner of the image that gets gradually changed to to a very magenta cast in the opposite corner of the image. i agree with victor that the image that eric submitted looks more like a white balance problem, not a lens cast problem.

pp
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 10, 2006, 01:30:36 pm
Hi Victor,

Have you used the 24mm digitar on the H25?  In the sample image you refer to had green on the left and magenta on the right.  I click-white balanced on the magenta to accentuate the green.  There is no place to click with the eye dropper to white balance an image with LC.  The very point is that the sensor is reacting to light coming at it from differing angles.  If I click on the right of the sample image I get green on the left.  Click on the left, get magenta on the right....  I used this this image because it is very extreme in the effect, but yet very easily correctable with the C1 pro LCC.  It works every time.  I have also spent a good deal of time with the H25 shooting on white seemless with a GX680.  The GX680 has swings and tilts with retrofocus lenses.  There is some ammount of LC in nearly every image (nearly every image also has a small ammount of swings and tilts).  I would never see this LC except for the fact I am shooting on white seemless where it is very easy to see a color shift of even 2 points magenta. Shooting other subjects with that camera I bet I would rarely notice any LC.

-Eric
Title: Alpa TC21 and Phase MF back?
Post by: narikin on October 10, 2006, 08:39:29 pm
I've never seen anything like that in 10,000 captures with my P45. at a loss to explain why you have that and I + many others dont. ever.
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 10, 2006, 09:04:17 pm
Quote
I've never seen anything like that in 10,000 captures with my P45. at a loss to explain why you have that and I + many others dont. ever.
[a href=\"index.php?act=findpost&pid=79861\"][{POST_SNAPBACK}][/a]


There are plenty of threads on the Phase One User forum about LCC.  The users over there talk about shooting the correction file like its a matter of course.  I have shoot with 6 different Phase One backs, all of them requiring correction.
-Eric
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 10, 2006, 11:56:51 pm
Quote
There are plenty of threads on the Phase One User forum about LCC.  The users over there talk about shooting the correction file like its a matter of course.  I have shoot with 6 different Phase One backs, all of them requiring correction.
-Eric
[a href=\"index.php?act=findpost&pid=79865\"][{POST_SNAPBACK}][/a]

there are many people who post their issues on the forum only to discover that later they could figure it out themselves. maybe, you should post your issues with phase backs on the phase one forum or contact phase support directly. i'm sure someone at phase one tech support would be happy to help you determine the cause of your particular problems.  i was surprised not to see even one post from you on the phase one forum given the fact that you've shot with 6 different backs and had various issues with them. leaf backs have lens cast problems and now it has an even bigger problem. . .centerfold problems. as a matter of fact, leaf (yair) are saying that: "This app not only fixes the "Centrefold", but it also addresses any colour shifts and lens fall-off/ vignetting."

pp
Title: Alpa TC21 and Phase MF back?
Post by: khwanaon on October 11, 2006, 01:05:53 am
Quote
I've never seen anything like that in 10,000 captures with my P45. at a loss to explain why you have that and I + many others dont. ever.
[a href=\"index.php?act=findpost&pid=79861\"][{POST_SNAPBACK}][/a]

why you have never had/seen this? simply because you did not have any comparison, a side by side comparison.

The color cast problem with Phase, Leaf and Sinarbacks is a fact, being it with MF bodies or shifts/tilts. How to handle this is another issue. I know that I dont have any problem with my Sinarbacks, being it my SB 54 H or my eMotion 75.

Once you have put side by side an corrected and non-corrected image, the problem will jum at your eyes!

Aon
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 11, 2006, 01:53:17 am
Hi PP,

I have not posted once on the Phase One forum because I have not had ANY issues with their backs.  I am in weekly contact with 4 other phase shooters I am friends with.  I have a very helpful camera dealer.  Most of my questions for Phase One were answered before they had an official user to user forum.  I have used their product happily since the 6mp LightPhase back (remember, the one that was a step-up from the H6 because it was 16 bit instead of 12 bit).  They work exactly as they are designed to.  Lens cast calibration is so well known and documented that there is no need to ask further questions.  I shoot a calibration file run the LCC and the files look perfect.
Title: Alpa TC21 and Phase MF back?
Post by: Eric Zepeda on October 11, 2006, 02:14:05 am
I use a cambo wds with 35 and 47 digitars and a P25. Lcc is just part of the workflow. As Eric said, doesn't mean the sensor is defective or anything, it's just what happens with wide lenses on the Kodak sensor. Honestly, I don't think it's that big of a deal...anyone remember CC filters, reciprocity failure and all the other things that went along with LF film? If Phase or Kodak improves things down the line, great. Until then I'll do what's necessary to deliver top quality files to my clients.
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 11, 2006, 12:35:41 pm
well said eric and eric. but i think it's important to note that people like myself who don't use wide angle lenses on large or medium format cameras with tilt and shift, but do use wide angles on cameras such as hassys or alpas in a non-shift capacity, might not ever see lens cast. i've shot calibrations and run lccs to make a point in order to show no difference between the files. If your shooting with tilt and shift, you're going to get lens cast no matter which digital back you're using.

pp
Title: Alpa TC21 and Phase MF back?
Post by: narikin on October 11, 2006, 06:41:46 pm
Quote
why you have never had/seen this? simply because you did not have any comparison, a side by side comparison.

The color cast problem with Phase, Leaf and Sinarbacks is a fact, being it with MF bodies or shifts/tilts. How to handle this is another issue. I know that I dont have any problem with my Sinarbacks, being it my SB 54 H or my eMotion 75.

Once you have put side by side an corrected and non-corrected image, the problem will jum at your eyes!

Aon
[a href=\"index.php?act=findpost&pid=79894\"][{POST_SNAPBACK}][/a]
sorry - its not that simple. of course I HAVE done comparisons and used the LCC card, and there is no difference with my main camera set up (Contax 645) yes, I know thats a retrofocus wide angle etc etc, but the point is that there's a lot of Phase users (the majority?) who are like me, use MF DSLR's, and dont see LCC ever. I'm sorry for those who do suffer, but please remember its non-existent as a problem for a lot of people.

Oh well, this thread is well and truly gotten hijacked to yet another LCC one, so thats the end of my original enquiry.
Title: Alpa TC21 and Phase MF back?
Post by: ericstaud on October 11, 2006, 07:20:45 pm
"sorry - its not that simple. of course I HAVE done comparisons and used the LCC card, and there is no difference with my main camera set up (Contax 645) yes, I know thats a retrofocus wide angle etc etc, but the point is that there's a lot of Phase users (the majority?) who are like me, use MF DSLR's, and dont see LCC ever. I'm sorry for those who do suffer, but please remember its non-existent as a problem for a lot of people."

If the thread you started had been about a retrofocus camera then what you are saying would make sense Narikin.  Using the Contax as an example of how your Phase back does not have LCC is pretty much hijacking your own thread.  The Alpa does not use retrofocus lenses.  Can you tell us which lenses you have used with the Alpa and the Phase One back?  You must have done this before to declare that LCC is off topic regarding the use a an Alpa 12TC and the P45.  

-Eric
Title: Alpa TC21 and Phase MF back?
Post by: Khun_K on October 13, 2006, 09:29:14 pm
Quote
"sorry - its not that simple. of course I HAVE done comparisons and used the LCC card, and there is no difference with my main camera set up (Contax 645) yes, I know thats a retrofocus wide angle etc etc, but the point is that there's a lot of Phase users (the majority?) who are like me, use MF DSLR's, and dont see LCC ever. I'm sorry for those who do suffer, but please remember its non-existent as a problem for a lot of people."

If the thread you started had been about a retrofocus camera then what you are saying would make sense Narikin.  Using the Contax as an example of how your Phase back does not have LCC is pretty much hijacking your own thread.  The Alpa does not use retrofocus lenses.  Can you tell us which lenses you have used with the Alpa and the Phase One back?  You must have done this before to declare that LCC is off topic regarding the use a an Alpa 12TC and the P45. 

-Eric
[a href=\"index.php?act=findpost&pid=80009\"][{POST_SNAPBACK}][/a]

I have P25 since 2004 and upgraded to P45 earlier this year, use on my Contax 645 with every Contax 645 lenses with satisfied result, plus sometimes using the MAM-1 adapter to use some Hassy CF/FE lenses.  Since I also own the Alpa 12W and AlpaSW and have ordered the back adapter CO645 for my P45, I was wondering if anyone has the experience using the digital capture back with the 38mm Biogon and 48mm Apo-Helvitar?  I have not yet bought the digital lens yet, but I am content to continue to use Contax may be until the Hy6 becomes a stable platform - as I shoot mostly fashion, and just use the Alpa as a wide angle solution ( wider than my Contax Distagon ) so I my priority will be either a 24mm Apo-Digitar or 28/4 Apo-Sironar, hay one use this combination and can recommend?
Title: Alpa TC21 and Phase MF back?
Post by: narikin on October 13, 2006, 09:51:51 pm
Quote
"sorry - its not that simple. of course I HAVE done comparisons and used the LCC card, and there is no difference with my main camera set up (Contax 645) yes, I know thats a retrofocus wide angle etc etc, but the point is that there's a lot of Phase users (the majority?) who are like me, use MF DSLR's, and dont see LCC ever. I'm sorry for those who do suffer, but please remember its non-existent as a problem for a lot of people."

If the thread you started had been about a retrofocus camera then what you are saying would make sense Narikin.  Using the Contax as an example of how your Phase back does not have LCC is pretty much hijacking your own thread.  The Alpa does not use retrofocus lenses.  Can you tell us which lenses you have used with the Alpa and the Phase One back?  You must have done this before to declare that LCC is off topic regarding the use a an Alpa 12TC and the P45. 

-Eric
[a href=\"index.php?act=findpost&pid=80009\"][{POST_SNAPBACK}][/a]

Eric, with respect, there's been dozens of threads about LCC, and Leaf Centrefold issues, and this one really need not go over that ground again... this is a pro forum, so do you really think that nobody is aware of it here?

there's plenty of other issues in the question of using an Alpa with a Phase - back wakeup, handling, focus, operability, shooting style, shutter choice etc. so there really is no need to go back over the same old ground once again. we are not all ultra wide angle shooters, and personally I would be using an 80mm or similar on an Alpa, ie: not retrofocus. As already commented, Alpa dont make any lenses, so I can use what I choose, including the Apo El Nikkor I have mounted up in a shutter + focus mount. but whatever, I give up, its just another LCC thread now.
Title: Alpa TC21 and Phase MF back?
Post by: hankg on October 15, 2006, 11:50:32 am
On the ALPA viewfinders. I was using the Linhof Multifocus optical finder that was made for the latest Linhof Technika 69 cameras. No distortion and incredible light gathering capability, also has parralax correction. ALPA can make a holder for it.
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 15, 2006, 04:10:19 pm
Quote
On the ALPA viewfinders. I was using the Linhof Multifocus optical finder that was made for the latest Linhof Technika 69 cameras. No distortion and incredible light gathering capability, also has parralax correction. ALPA can make a holder for it.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=80505\")

i'm not not acqainted with the linhof multifocus finder, but will this adapter work:

[a href=\"http://www.alpa.ch/en/products/pictures/_l/Negative0-25-25.jpg]http://www.alpa.ch/en/products/pictures/_l...tive0-25-25.jpg[/url]

or this:

http://www.alpa.ch/en/products/pictures/_l/ALPA_AAUS_02.jpg (http://www.alpa.ch/en/products/pictures/_l/ALPA_AAUS_02.jpg)

just wondering. . . .

pp
Title: Alpa TC21 and Phase MF back?
Post by: hankg on October 16, 2006, 12:55:39 pm
I don't have the camera any more but the small one with spirit level looks like it. You can see the finder mounted on the Linhof here: http://www.linhof.de/english/kameras/techn...ertechnika.html (http://www.linhof.de/english/kameras/technika/supertechnika.html)

here is the 4x5 finder at B&H:
http://www.bhphotovideo.com/bnh/controller...oughType=search (http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=31203&is=REG&addedTroughType=search)

Here is a 6x9 finder on ebay:
http://cgi.ebay.com/Linhof-Multifocus-Otic...1QQcmdZViewItem (http://cgi.ebay.com/Linhof-Multifocus-Otical-Viewfinder-6x9_W0QQitemZ280037860382QQihZ018QQcategoryZ43479QQssPageNameZWDVWQQrdZ1QQcmdZViewItem)

If you are patient you will be able to get one on ebay. New they are very expensive and I am not sure they are in production. I had a 6x9 film back on the Alpa so it was a perfect match with digital you might have to alter the mask (the masks are changeble and come in 6x6, 6x9, 6x7 formats).
Title: Alpa TC21 and Phase MF back?
Post by: pixpop on October 16, 2006, 04:40:31 pm
Quote
I don't have the camera any more but the small one with spirit level looks like it. You can see the finder mounted on the Linhof here: http://www.linhof.de/english/kameras/techn...ertechnika.html (http://www.linhof.de/english/kameras/technika/supertechnika.html)
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=80695\")


this too would probably work:

[a href=\"http://www.badgergraphic.com/store/cart.php?m=product_detail&p=1286]http://www.badgergraphic.com/store/cart.ph...t_detail&p=1286[/url]

pp
Title: Alpa TC21 and Phase MF back?
Post by: Gary Ferguson on October 16, 2006, 04:57:38 pm
Quote
I was wondering if anyone has the experience using the digital capture back with the 38mm Biogon


I regularly use a P25 with a Hasselblad 903 SWC, there's a very minor colour cast issue but it's easy to solve because with no camera movements possible on the 903 you soon build up a small library of correction shots at different apertures, portrait and landscape format, and different lighting conditions. The 38mm Biogon vignettes noticeably, and I get the impression the vignetting is more obvious with a digital back than with film. I've thought about a generic centre filter but unless these are matched precisely to one specific lens you can end up with a darker annular ring that's hard to edit out. Another reason for avoiding a centre filter is that the 38mm Biogon can't take two stacked filters and I often use a polariser.