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About the Phase One H25....

young'ee

New member
Looking for information on the Phase H25 back.

As far as I know the H25 is the same sensor/electronics as the P25....its just the H25 is tethered and the P25 is self contained. Does anyone here know if this correct ?

Is there any other interesting information about the H25?
 

young'ee

New member
Thanks B L ....was starting to get lonely there for a while.

Does anyone know the sensor model number for the H25? Is it the same as the H20 or different ?

Are the Sensors on the P20 different to the H20 and is the sensor on the P25 different to the H25?

Anyone with user experience on either of these 2 backs? I know its from the dim dark ages ago, but I love the 9 micron pixels (and yes I read the fat pixel thread over and over again - cant get enough of the fat pixels)
 

dougpeterson

Workshop Member
Does anyone know the sensor model number for the H25?
Kodak KAF-22000


Is it the same as the H20 or different ?
These share the same Kodak 22mp 9-micron 48x36 rectangular sensor: H25, P25, P25+
These share the same Kodak 16mp 9-micron 37x37 rectangular sensor: H20, P20, P20+


-----

Limitations to be aware of before buying
- all four backs require firewire with solid/reliable power when shooting tethered. The P series had batteries but the P20/P25 could not bypass the firewire power supply when present (like the later P series and P+ could). The H20/H25 is tether only. No portable shooting at all.
- all four backs are 30-60 second max exposure lengths (at base ISO, normal temperature)
- all four backs moire very easily on clothing, architectural features, or other repeated patterns.
- all four are no longer supported by Phase One
- all four can have calibration-line issues
- The H20/H25 have flash sync ports that are sodered and can't be replaced by a dealer; the P20/P25 sync ports are dealer-replaceable
- The internal capacitor on many (most?) P20/P25 will have worn out by now, such that the internal clock no longer holds the time between power cycles.
- P screen was very basic and could not really be used to judge focus (if you worked with it a ton you could get used to judging the focus, but since zero sharpening was applied to the preview image most viewers had a heck of a time doing any focus checking). That said, the histogram was useful. H, of course, had no screen, but if you're using the H you are tethering and using the computer for exposure/focus checking.

My personal opinion is that the "fat pixel" thing is not really a "thing" in that it's not a unique/different look compared to other Phase One digital backs beyond being low in resolution and having CCD Sensors. I think the mythology around them comes from the people who shot with them (typically very talented) and the way they were shot (slow and considered, as there was no, or useless, live view, and low ISO). However, I do not assert this with absolute confidence, only share it as my best-guess based on my experience.

The number one thing to know about these backs is they are based on 2001 sensor technology. Phase One backs remain competitive in image quality to cameras for many years after they are released, but 17 years is a long time in sensor tech development. Color, dynamic range, and ISO performance simply do not compare to modern systems. For low-ISO, short exposures with flash you might be surprised how well an H20 raw still compares to a Canon 5D Mark IV, but it won't remotely touch a more recent Phase One back.

That good thing is the price. The above limitations, and the age, limit the demand. The fact that P1 backs are built-like-a-rock and last and last, help with the abundance of supply. Therefore the used-marked-no-warranty-or-support price is very low, especially for H20 and H25.

I'd suggest, if at all possible, to play with one before you buy. But that's the same advice I'd give regardless of which back/brand you were considering.
 

young'ee

New member
Doug, many thanks for your input - goldmine of very useful information as always.

Great to get such detailed information.

What about the P25+ - that goes beyond 60 seconds exposure doesn't it ?

As for the others I understand all the limitations. I have a high end back for those times I need it but for now this is a 9 micron thing that I am exploring. Hence want to use as many of these backs as I can. Subject matter is landscape/flowers/trees, so I think these backs will cope with that - if not I am going to find out the hard way.

I guess its like people who have an interest in old cars. New cars are so much better, but old cars have a charm to them. So the 9 micron backs.

Thanks for your very detailed input. Its nice to have it here because its there for reference for others as well as time goes on.
 

young'ee

New member
Doug, if I may impinge upon your generosity one more time......

The H25, P25 and P25+ are all the same 48x36 rectangular Kodak KAF-22000. Got that.

What about the H20, P20, P20+ 37x37 rectangular sensor ? are they also the KAF 22000 or a sensor model earlier ?

I think there was a Kodak KAF-16800 sensor or a number close to that anyway. Perhaps it was this earlier sensor that was in the H20/P20/P20+ ?

I am not sure, hence asking.
 

steve_cor

Member
I found this with Google, but other than that, I don't know anything about it.

Kodak 16mp 9-micron 37x37 square sensor: the Kodak KAF-16802
 

young'ee

New member
Thanks Steve. It all adds to the knowledge bank.

These backs are so old most have probably long forgotten them.

The multi shot backs are intriguing.
 

Charles S

Well-known member
Thanks Steve. It all adds to the knowledge bank.

These backs are so old most have probably long forgotten them.

The multi shot backs are intriguing.
Not a P1 back, but....the original Imacon/Hasselblad backs used the same sensor in the V96C etc backs. These backs could be used on the V Blad and with adapter plates on other brands.

Someone in an earlier post made a statement about fat pixel effect being a myth, and I wanted to add my 2c based on my prioir ownership of a V96c attached to a V series Blad. From this system I upgraded to a 13 year old H3 Blad about a year ago. So different sensor and lenses. In the process, I gained 2 stops ISO and AF, which made the camera more usable.
However, I lost a painterly effect to the images that I can't recreate. It might be that the Zeiss glass, or the sensor. Someone with a V to H adapter might be able to break it out between the lenses and the sensor, so please jump-in. All I know is that the images "feel" less painterly and more neutral.
 

Charles S

Well-known member
And then a H20 back popped-up in a local classifieds site for 400 USD. And the rest is history.
Figured out how to get a FW 400 card working on an old laptop. Figured out the latest version of C1 that will run on it. Figured out how to power the FW cable. Had some difficulty with the flash sync, but by trying different cables this works now too. Next shoot is on Thursday, I can't wait.
 

dave.gt

Well-known member
And then a H20 back popped-up in a local classifieds site for 400 USD. And the rest is history.
Figured out how to get a FW 400 card working on an old laptop. Figured out the latest version of C1 that will run on it. Figured out how to power the FW cable. Had some difficulty with the flash sync, but by trying different cables this works now too. Next shoot is on Thursday, I can't wait.
Ooooh...Charles, please keep us updated with the results!:grin:
 

Charles S

Well-known member
Ooooh...Charles, please keep us updated with the results!:grin:
The shoot went well.
I have been shooting with an H blad for the last year and a half, and now going back to the V was a bit of an adjustment. The reason to go the H was AF, since my eyesight has deteriorated. But being spoilt by the bright viewfinder, going back to WLF on GG was a bit of an adjustment. But it was fun to shoot again this way.

The back lost the connection to the laptop once or twice, but pulling the cable out and reinserting it fixed the issue.

DR is pretty limited so you need to nail the exposure and be careful with contrasts. You need to watch the histogram like a hawk. For slow deliberate shoots, this works fine.

I haven't spent time understanding C1 so i just took the raw files and processed them in LR. Supposedly C1 is superior, but it is another program to learn, besides LR / PS / Phocus, so I can't be bothered.

The files have a nice grain to them. The skin tones are lovely.

One of the images of the shoot you can find in the NSFW section for obvious reasons: https://www.getdpi.com/forum/artful...uding-nsfw/65208-classic-nude.html#post774904
 

gegeger

New member
Looking for information on the Phase H25 back.

As far as I know the H25 is the same sensor/electronics as the P25....its just the H25 is tethered and the P25 is self contained. Does anyone here know if this correct ?

Is there any other interesting information about the H25?

Hello i'm from argentina and i saw a listing of a H25 and i can't find correct information about it.
Can you help me in what i need to test it?
My notebook doesn't have FireWire and seller says that usb to FireWire adapter doesn't work because it needs more energy. Can you help me? And what is the exactly version to thether the back?
If you can make a tutorial i would be pleased! :clap:
 
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