The GetDPI Photography Forum

Great to see you here. Join our insightful photographic forum today and start tapping into a huge wealth of photographic knowledge. Completing our simple registration process will allow you to gain access to exclusive content, add your own topics and posts, share your work and connect with other members through your own private inbox! And don’t forget to say hi!

Why no IQ240

Dogs857

New member
Ok correct me if I am wrong here;

As I understand it, the IQ140 and 160 are basically the same sensor, only the 140 is smaller which gives it the 40mp size.
Now with the release of the IQ250, and it's limitations with technical cameras, why doesn't Phase release an IQ240?? Same as the 260 but with the crop sensor and 40mp.
They seem to be lacking in backs that can handle long exposures with tech cameras and the 240 would be a better upgrade for those still holding onto a P45+ that don't want or need the 260.

Just a thought, but I would buy one.
 
The IQ260 doesn't do long exposure better than the P45+, so why bother with something like an IQ240?

I am very shocked by how poorly the IQ260 does long exposure. You might want to consider the Sony CMOS instead (e.g. CFV-50C, Credo 50, IQ150, IQ250) if you can afford the Rodenstock Digaron-W or Digaron-S lenses.
 

Dogs857

New member
Yes I have seen your detailed post on the 250.

Thing is I have just gotten back to MF digital and picked up a P45+ as there was very little other option. I wished at the time that there was an IQ240 available as I use a tech cam and the 250 doesn't play well with wide lenses and movements.

The 45+ is great, and this is really a theoretical post as I can't see Phase releasing a 240.

I just wish they had. Smaller sensor, good LE and tech cam friendly.
 

tjv

Active member
The CMOS back does actually play quite nicely with movements, providing you use Rodenstock retro focus wides and know the limits. I'd say the advantages of the CMOS technology generally outweigh the negative aspects, especially if you don't need a larger chip.
 
The P45+ was based on a different design and is not comparable to the 40MP sensor that was in the last batch of backs/cameras, which have no LE capability. The long exposures of the P45+ had to be scrapped to make room for the "Sensor+" technology, and P1 had to work hard to bring it back into the IQ260 while keeping Sensor+, there was a whole article on LuLa about that.

The 40mp sensor that is in the 645D, Leica S/S2 and recent digital backs was kind of a dead-end thing IMO. It did have nice colors and I liked the output from using the Leica S and 645D, but with limited ISO and ~12 stops DR there is only so much you can do with it besides "straight" photography, where you ETTR and the exposure you get is mostly the image you'll end up with, minus creative photoshopping. For photographers used to nailing perfect shots in the studio or with controlled lighting, this really wasn't a limitation at all, but if you are an "available light" photog and are at the mercy of nature and the DR/noise of your camera, the Sony sensors really do kick butt.

It is a shame that high-density sensors expect so much from the lens in front of it, but it's they way we've seen them going for a long while now, glass is increasingly becoming larger and "over-designed" to keep increasing megapixel counts satiated. If you told someone 15 years ago that a small format 55mm f/1.4 would need to weigh a kilo and cost $4000 to fully resolve the medium, you would get strange looks indeed.
 

Paul2660

Well-known member
The P45+ is a 1:1 crop and the 250 is a 1:3 cropped sensor. If the 250 had come out in a 1:1 it would have been much more tempting.

I also believe the 39MP sensor in the P45+ was unique to Phase One and the P45+. Hasselblad and Pentax used a different version of the Kodak 39MP chip, but I might have this incorrect.

From what I have seen from the tests on this site by Voidshatter, the IQ250 seems to work better with movements with the old Rodenstock HR lenses with the 70mm image circle. When you move to the HR-W glass and start to shift to 12 or 15mm you start to see pretty harsh color shifting especially in the blues.

I would also agree that the IQ260 does not have the same long exposure range as the much older P45+. Maybe in the right conditions 30 min but that may be a push.

Paul
 

torger

Active member
As far as I understand Hasselblad used the exact same sensor, the KAF-39000, but only Phase One managed to get long exposure out of it which requires som exceptional analog design.

In a way, a more logical upgrade for P45+ users would have been a "P50+", based on the same sized 50 megapixel KAF-51000 sensor, now only used by Hasselblad in H5D-50, and the H4D-50 I just got myself (and the older H3DII-50). But I guess Phase One thought it was a too small step and wanted to migrate to Dalsa sensors which performs a little bit better in almost every aspect except tech wide angle compatibility. Only the Kodaks can do a symmetrical wide like the Schneider Digitar 28/5.6 to the 90mm image circle edge.

I like the 48x36 / 49x37 crop size, but I understand if the camera makers think it's too small step 44x33=>49x37=>54x41 and got rid of the middle. Hasselblad *might* want to keep the 49x37mm size as they have some glass and viewfinders made for it, but with Kodak gone I don't know how easy it is to make someone else like Sony to make a custom size only for them.

Well, Dalsa actually has a 48x36mm crop of their 6um technology, as far as I know only used by the Sinar eXact tether-only back.
 

ErikKaffehr

Well-known member
Hi,

Those 55/1.4 lenses were not anywhere near sharp at large apertures, not on film and on digital. I have had three of those (for Minolta).

The reason that the Distagon 55/1.4 is so large/expensive is that it needs to perform near optimum at maximum aperture. Sigma achieves essentially almost the same performance at 1/4 the price.

It seems that the Sony 55/1.8 is also a very good performer, obviously not at f/1.4, but at a much lower weight.

Regarding the IQ-240, I don't know. I guess that Phase One is happy working with Dalsa on sensors. Last time I checked the IQ-140 was still around. But, as far as I recall the 40 MP sensors used to have micro lenses that didn't play well with large beam angles, while micro lens design on the newer sensors works well non retrofocus technical lenses.

I would also say, that I would agree that my P45+ doesn't have the DR of a modern Sony sensor, but it is not that much of a difference. But, I have also been told that I have a very good sample.

Best regards
Erik

The P45+ was based on a different design and
It is a shame that high-density sensors expect so much from the lens in front of it, but it's they way we've seen them going for a long while now, glass is increasingly becoming larger and "over-designed" to keep increasing megapixel counts satiated. If you told someone 15 years ago that a small format 55mm f/1.4 would need to weigh a kilo and cost $4000 to fully resolve the medium, you would get strange looks indeed.
 
Last edited:
Hi,
The reason that the Distagon 55/1.4 is so large/expensive is that it needs to perform near optimum at maximum aperture. Sigma achieves essentially almost the same performance at 1/4 the price.
Almost is not quite the same as "the best, bar none", but I get your point. The thing is that wide aperture performance is generally the benchmark for lens quality since any lens is good by f/8-11 whether it be a $200 used bargain or a $5000+ state of the art digital optimized monster, but f/8+ is practical for only a handful of situations (judging by the fact that most MF shooters do landscapes and arch, they'll say otherwise I'm sure).
The 55, 120 and 150mm lenses I have for my 645Z are astonishingly sharp at f/8 to a relatively equal degree over 85% of the frame, but I do wish the system had lenses that could pull that off at f/2.8 at least.

Ideally, a lens should display optimal performance from maximum aperture and only gain depth of field from stopping down, otherwise saying that an old lens from way back when is good as the latest Zeiss stopped down is like saying your economy SUV is a better performer than a Ferrari on a city street at rush hour.
 
Top