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DT Tech Cam Test - IQ250 vs IQ260 vs IQ280

gerald.d

Well-known member
I have an IQ250 and the 32HR. If you can let me know exactly what you're after, I'll try to take some shots in a few days (so far I've only used it unshifted on the FPS, but I have a Max so can use that).
 

Paul2660

Well-known member
With the IQ250 I think the issue is the proximity of the of sensor to the rear element of the lens in use with a tech camera, in that the close the rear element is to the sensor, the more issues with color sat loss on movements will occur.

I can provide a bit of feedback, from tech camera lens standpoint. I recently was able to test the Arca M2, setup for a DSLR mount, sold as the DSLR2. With this setup, you can mount a Sony A7r and use almost all of the current lenses from the tech lineup, exceptions, (23 Rod, 28 Rod). The wider the lens, the closer it has to come to the sensor, so I expected good results with the 60XL and 90mm Rodenstock and OK results with the 40mm Rod and 35XL.

I realize the A7r is not the same size, or MP as the Sony sensor in the MF cameras now on the market, however I believe the Sony 35mm sensor and the MF cousin have similar characteristics. The Sony 50MP sensor in the various MF cameras out there, Phase, Hasselblad, Pentax is the same base sensor, and it uses micro lenses. Extreme shifts on these types of sensors, does seem to have issues. I don't know if the individual pixels on the 35mm Sony are larger or smaller than the pixels on the 50MP version, it's my thought that they would be larger.

What you are going to see with shifts up to 10mm, is excellent to good results, dependent on scene. As you approach 10mm, you are going to start seeing more color/sat fall off, no loss of details. On shifts up to 15mm you start to see significant color/sat fall off, as much as I feel 40% maybe even 50% depending on the lens used. Past 15mm and things really fall apart. You hit the edge of the sensor by around 18mm anyway, so pushing to 20mm was moot.

Of the lenses I used, I found the following: LCC's were shot with each.

35XL, excellent on center, good to 5mm shift, OK to 8mm of shift, very harsh color loss past 8mm and strong magenta cast.

40mm Rod, excellent on center, good to 10mm shift, Very harsh color/sat loss by 15mm

60XL excellent on center, very good to 10mm, good to 15mm, useable at 18mm but some work required on color recovery. CF was used on 60XL

90mm Rod, excellent all the way to 18mm.

You can assume the 50MP CMOS in the Phase IQ250, will have similar results with tech lenses. Maybe a bit better but the loss of color/sat on shifts of 12mm or more is pretty considerable. The 32mm Rod may do a bit better, but when you look at the total cost of that lens I can't see the justification if you are going to be limited to 12mm or so of shift.

Is recovery possible with LCC?
Yes and No.

Yes, in that I found most times in C1, I could recover the loss of green saturation and hue on extreme shifts, not perfectly, but enough that I could make a print.

No, in that a blue sky is very hard to balance out as the loss of blue hue/ color shifts is the hardest to recover. This is especially true if the sky is pure blue with no clouds to help break it up.

The amount of time in post to recover the files to me was extreme mainly due to the color/sat loss on shifts.

What Gerald is seeing with his IQ250 and the TS-E lenses is totally different as with these lenses, the lens is farther back from the sensor (as I understand the setup), thus the color sat loss issues will be much less extreme to none. The 24 and 17 TS-E's are designed to work with a mirror box which should allow the lens to be much further from the sensor at infinity.

Just how close you have to come with the 35XL is around a 1/8" gap, and the 40mm Rod is around 1/4". The 60XL allows for a much healthy gap, approaching around 1/2".

Paul
 
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tjv

Active member
Thanks for your comments, Gerald and Paul.

I guess I'm hoping that this Sony sensor is somewhat of a magic bullet, particularly when I think of it in the context of Hasselblad's new CFV-50c and Nick-T's assertion that live view can be enabled on it via a Firmware update (I'd NEVER buy on rumors though, just to make that clear). I think the IQ250 represents the gold standard when considering interface, internal battery and software, but it's hard to argue with the price difference between the two products.

Anyway, I'm hoping that this sensor might give me all the movements and versatility I require when mounting on my Linhof Techno. My first look at the DT test comparisons led me to believe that the IQ250 pretty much trounced the IQ260 in every aspect of image quality. Subsequent reading (mainly of this thread) and looking at the files suggest otherwise, however.

For my purposes I need to be able to use a 25/28mm equiv. lens (35mm terms) and be able to employ an absolute maximum of 18 to 20mm rise / fall. I'd also need to be able to employ 2 or 3 degrees of tilt in conjunction with up to 10mm rise / fall. I am a documentary and fine art photographer and mostly shoot landscapes and urban scenes, with the occasional environmental portrait. Colour is very important to me, which is why I've stuck with shooting film and scanning on an Imacon 949 for so long. I guess this new generation of CMOS DMF backs has me exciting because the exposure latitude / DR seems amazing, the on back live view will do away with the need for using a sliding back adapter (I don't stitch) and, in terms of the Hasselblad at least (providing they do implement LV) the price is becoming more attractive.

Anyway, I was just wondering if anyone out there is using an IQ250 on a tech camera and what they think about the performance within the technical requirements I've listed above. I'd be very worried about colour fidelity of things like blue skies, green grass, etc. There's no point investing this kind of money in something that only gives you a portion of what you need. I'm guessing people are going to say that for what I want the IQ260 is still the gold standard, but I live in hope.

Thanks again,

TJV
 

dchew

Well-known member
With the IQ250 I think the issue is the proximity of the of sensor to the rear element of the lens in use with a tech camera, in that the close the rear element is to the sensor, the more issues with color sat loss on movements will occur.
...
Paul
Paul,
The work you did with that set up was very enlightening; thank you for the effort. One point about the proximity of the rear element. In general that's correct - the closer the element is the worse the color issues. However, it is really the angle of incidence at which the rays hit the sensor. For example, one could imagine a lens that has a rear element only mm's from the sensor, but if that element was huge, and hence projected light rays out of the lens perpendicular to the sensor, there would be no cast at all. There may of course be other serious problems with such a design!

I bring this up because I am about to receive a 60xl. I am very curious how the 60xl does vs. the 70hr, and relative to the 40hr. the 60 fills the gaps in my lenses a bit better than the 70, and I also hope it to be a great single-lens choice when going really light. I'm sure its cast is worse than the 70, but I wonder by how much. Your report shows it is actually better than the 40hr, which is encouraging. I have the IQ180, so your results won't correlate directly with mine, but encouraging non the less.

Once I get the lens, I should also be able to borrow a 250 from my dealer. I could do some "quick" (ha!) comparisons of these three lenses sometime in the next few weeks.

Ciao,
Dave
 

f8orbust

Active member
The only solution I see going forward with WA lenses / tech cameras and CMOS DBs is a new generation of (even) stronger retro-focus lenses.

Just can't see P1/Leaf, HB, Leica, Pentax or Sinar getting Sony to make a chip that behaves well with large movements using the current crop of WA lenses. Sony probably only wants to fabricate one MF chip and then sell it to as many OEMs as possible; Leica and Pentax have no need for a chip that behaves well with large movements for a start, so that puts even less pressure on Sony to alter the design. Most DB users probably use their DB on an SLR-style body, so they'll be happy with the current low noise/high ISO CMOS implementation.

In the short term, I think the most flexible tech-cam solution is something like a P45+ for large shifts, with an IQ180 for single high-res shots. Both together should cost less than a used IQ260. If small movements are required and you have R/S WAs, then the CFV-50c is an attractive proposition. If no movements are required - e.g. you shoot with an Alpa TC - then the CFV-50c is a no-brainer. I'd rather have the low noise / high ISO / long exposure capability / $20k saving of the CFV-50c than the extra 10MP of the closest competing CCD back, the IQ260.

Jim
 

tjv

Active member
Thanks. Yes, I think I've been lost in some very wishful thinking regarding the CFV50c / CMOS MFDB. If I'm being practical, I think I'll likely end up with an IQ160 and have to suck it up and use a sliding back.
 

Ken_R

New member
Thanks. Yes, I think I've been lost in some very wishful thinking regarding the CFV50c / CMOS MFDB. If I'm being practical, I think I'll likely end up with an IQ160 and have to suck it up and use a sliding back.
I compose using the Live View on my IQ160 back. Yes it is not a high quality live view but works. In bright light it requires the use of a ND filter which I carry anyways. For focusing it is barely adequate in some situations but between it and using focus mask it can be done quite precisely.

I use the back on a Arca Swiss RM3Di with Rodenstock 40mm and 70mm HR-W lenses.

I love the setup works well for everything except night photography and extreme high iso but from dawn till dusk it is my favourite rig for landscapes.

The IQ250, from what I have seen posted so far, seems to work superbly with SLR lenses so the best choice for wide angle work with that back would be either one of the SLR systems (Hasselblad and PhaseOne/Mamiya) that have good wide angle lenses available but if you want tilt and shift with extreme wides the only choice would be an Alpa FPS system and Canon TS-E lenses. (Hartblei H1 might work as well). Of course the IQ250 works very well with longer tech camera lenses but that is not the issue.

The Benefit of the IQ160 and 260 backs is that they work well with almost any lens made today all the way down to the 23mm Rodenstock which on a sensor that large is equivalent to a 15mm lens on a 35mm full frame format DSLR.
 

tjv

Active member
Hi Gerald.D.
If you have time, I'd very much appreciate seeing some examples of the 32HR shifted on the IQ250. Any examples would be handy, really. I'm curious about performance more than anything, so not urgent, but I'm sure others would be interested too.
Thanks,
TJV
 

gerald.d

Well-known member
Hi Gerald.D.
If you have time, I'd very much appreciate seeing some examples of the 32HR shifted on the IQ250. Any examples would be handy, really. I'm curious about performance more than anything, so not urgent, but I'm sure others would be interested too.
Thanks,
TJV
Hiya - bad timing I'm afraid as I'm literally about to jet off on vacation sans anything MF (sat in the airport bar as I post this!) . Back in a couple of weeks though and will do a thorough test then.

Kind regards,

Gerald.
 
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