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Dalsa vs. Kodak chips

archivue

Active member
i find that i tend to prefer the overall look of images took with an Aptus 22 and digital lenses at 25 iso... and limited in long exposure !
So, for whom who had that type of back previously, when you are using your new back, what are the Big plus except ISO and long exposure over the Aptus 22 ?
 

yaya

Active member
Perhaps one area that has not been discussed is Dalsa's ability to handle fall-off (luminance and focus) better due to the pixels' active area seating closer together.

This is mostly visible if both are tested on a tech WA camera with some shift at the same f-stop and reason why some architecture photographer choose Dalsa over Kodak.

Yair
 

thomas

New member
Perhaps one area that has not been discussed is Dalsa's ability to handle fall-off (luminance and focus) better due to the pixels' active area seating closer together.
Yair, I'm a bit confused... are you referring to Dalsa vs. Kodak in general or to Dalsa with 6micron sensors vs. Kodak with 6.8micron sensors?
If you are referring to the latter: it would be new to me that a higher pixel count (on the same image area) produces better sharpness at the edges - I always thought it's exactly the other way around. In the case that a lens resloves perfectly for both pixel "sizes" the smaller pixel pitch has of course an edge as the same image area produces higher resolution.
From my experience: on a 9micron chip sharpness falloff is less obvious than on a 6.8micron chip with the same lens.
Or did I get you completely wrong?
Thanks!
 

Jack

Sr. Administrator
Staff member
I have struggled off and on for a few years to find specific technical details on the differences between a Kodak CCD and the similar Dalsa CCD without much success. All I've ever been able to glean aside from the well flushing and power differences is that the Dalsa design is indeed thinner and the photo-sensitive silicon layer is closer to the top of the well; and that while they both use a bayer filter, the design of the Dalsa is different than Kodak's.

Shallower wells mean less cosine falloff and tunnel shading as the angle of incidence increases, and this would at least in part support the results I see of less color shift and fall-off effects when used on a tech camera.

As for the Bayer filter, I've never been able to get any concrete specifics. I've found allusions to the effect that the Dalsa filter uses less dense colors in their filter, but I suspect that was based on somebody seeing one and making a casual visual comparison. I can only suspect that the Kodak is using GRBG and Dalsa is perhaps using RGGB or even CYGM as an alternative (which would look less dense on casual comparison), but have no evidence. My empirical data suggests the Bayer matrix is indeed different though, as for whatever reason profiling cannot seem to generate an identical color response across the visible spectrum between both sensors. Finally, Bayer worked for Kodak when the GRGB and RGGB matrix was patented, so again, another possible reason for the CYGM assumption for Dalsa. So basically all I can say is I have a strong hunch that Dalsa uses a CYGM pattern in lieu of one of the traditional primary Bayer patterns.

One thing is for certain, all this will change as the newer panchromatic filtered sensors make their way into MF capture...
 

Analog6

New member
I have not been too much into the technical side - which backs have which sensors - to keep in mind when I upgrade?
 

yaya

Active member
Yair, I'm a bit confused... are you referring to Dalsa vs. Kodak in general or to Dalsa with 6micron sensors vs. Kodak with 6.8micron sensors?
If you are referring to the latter: it would be new to me that a higher pixel count (on the same image area) produces better sharpness at the edges - I always thought it's exactly the other way around. In the case that a lens resloves perfectly for both pixel "sizes" the smaller pixel pitch has of course an edge as the same image area produces higher resolution.
From my experience: on a 9micron chip sharpness falloff is less obvious than on a 6.8micron chip with the same lens.
Or did I get you completely wrong?
Thanks!
9µ Vs 9µ
6.8 Vs 7.2µ
6µ Vs 6µ

Kodak's wells are deeper (as Jack describes) and use "gutters" for light "overflow" whereas Dalsa's are shallower with no gutters (overflow goes through the thinner silicon layer). Closer wells help to improve falloff control and produce a slightly sharper image overall.
If I'm not mistaken most if not all Bayer sensors use RGGB pattern.
 

fotografz

Well-known member
I've been debating this one myself for some time Woody, and haven't fully decided yet.

The 60 is tempting, but one point that I haven't decided on yet is that the H4D/50's native ISO is 50 where the H4D/60's is 100. Sounds like a small issue, but having used a Leaf Shutter H camera with an ISO 100 base (H3D-II/31), there were times I wished for 50 ... and ISO 50 is what I always use in the studio with strobes. Both top out at ISO 800 and have the same capture rate.

With the newest version of Phocus and the latest firmware, the H3D-II/39 can do 64 second exposures. Hassey lists the H4D/50 at 32 seconds ... and it remains to be seen if they goose that up like they did with the 39 recently. Hassey hasn't published the long exposure specs for the H4D/60 yet (that I can find).

BTW, I don't think use of the HCD lenses reduces the 60 to 50 ... the crop factor is minimal as I understand it, and I'd guess the 60 becomes a 55 or so (that would be splitting the difference between the two sensor sizes). No clue how the edge performance will be with the HCD lenses, but I'd suspect DAC corrections for some of it if there are correctable issues.

I haven't used the later versions of a Dalsa sensor ... my last experience was with my 33 meg Leaf Aptus 75s. So it is hard to comment on. I do know that the Hassey 50 has received good reviews compared to the Kodak 39 in terms of cleaner, more natural color rendition and great skin tones, so it's hard to use any Phase experiences here because there is no Phase One 50 if I'm not mistaken.

What recently caught my eye is that Hassey included the H4D/50 Multi-Shot in their trade Program ... which is only $3,000. more compared to trading a H3D/39 for a H4D/60. That, more than anything is where my debate lies since a H4D/50 Multi Shot is probably the highest IQ camera they make for certain applications ... while still providing single shot 50 capture.

-Marc
 

Jack

Sr. Administrator
Staff member
I'm not a Hassy guy, but it sounds like a no-brainer to me -- the crop is virtually insignificant and 50MP is not a whole lot different than 60. But what is really different is having multi-shot when you want it -- the enhanced results there are real. ISO 50's a plus too...

My off-the-cuff thinking...
 

Guy Mancuso

Administrator, Instructor
I like having ISO 50 now. It really comes in handy when you need to get some slow shutters for shooting water and such. That extra stop in speed can make all the difference sometimes. Multi shot is certainly nothing to sneeze at. For product work WOW
 

fotografz

Well-known member
Thanks you two ... it makes it even harder to ponder with that input. :eek:

I've toyed with the notion of MS for a long time ... and most of the Shooters that I hired as an Art Director (that used Hassey) used Multishot in studio.

Amazingly MS virtually eliminated any post work especially with fabrics and such ... I do a fair amount of Bread & Butter studio jobs like that (fabric samples for automotive companies to use for dealer sample charts and catalogs) ... and lots of wheels. Not as easy to shoot as it sounds ... trust me.:eek:

Like this 3" fabric sample and a super close up crop of it ... or this "bitch to shoot" chrome wheel which is as shot with no retouching yet except to knock out the background ... Both done with the 39.

50/MS would capture these even better and provide for cleaner, more subtile detail.

I'm talking myself into this ...:ROTFL:

-Marc
 

Jack

Sr. Administrator
Staff member
Nice job on the wheel --- but I found your (or an assistant's) reflection in it! :ROTFL:
 

fotografz

Well-known member
Let's play "Where's Waldo?" :)

Couldn't be my assistant Jack ... they've slashed prices paid to the bone, so I have to do these by myself. :(

-Marc
 
I would also like to point out that the H4D50 uses a Kodak TRUESENSE CCD which is a totally different design and architecture to the earlier Kodak CCDs.

Most users who have upgraded from 39>50mp are always very complimentary of the improvements they see in the look of the sensor.

Mostly, tonality, highlights, shadows, colour rendition. It is really a delightful sensor to use, photographically.

David
 

Guy Mancuso

Administrator, Instructor
David so what's new the clock is stuck on 18 hours with a question mark. Can you speak now or still on hold.
 

Guy Mancuso

Administrator, Instructor
Thanks David always nice to have the Hassy folks here keeping us updated on the latest stuff. I'm a big proponent of the whole industry at large regardless of what I shoot. Actually I may wipe the name off mine and rename it Mr.Gear Slut. LOL
 
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