IQ3 100MP technical camera tests: color cast, mazing artifact, tiling issue, DR etc

[voidshatter]

Edit: note that the 3100 image was even 1 stop under the 180 image. I matched exposure and color on the wall to the left. These are both 100% crops from the upper left of an image (40hr).

Thanks for reproducing the issue I have found!

There is also another side note: the more shadow push applied, the more purple fringing appears. If you bracketed for your test shots, you could also try a brighter shot of the IQ3100 image - it may have less CA.

It is strange though that neither the IQ380 nor the IQ250 had such purple glow.

 

[Paul2660]

In the example is the 180 image on the right of the two vases? I am assuming this so due to shot count?

Both images show it the image in the left obviously has it in a greater amount and it's brighter.

Wonder if the defringe tool in LR would remove this effect. C1 has no such eye dropper tool that I am aware of.

Paul C

 

[dchew]

In the example is the 180 image on the right of the two vases? I am assuming this so due to shot count?

Paul C

Yes. I should have said that, but hopefully solving my little mysteries makes this a little more fun!

 

[dchew]

There is also another side note: the more shadow push applied, the more purple fringing appears. If you bracketed for your test shots, you could also try a brighter shot of the IQ3100 image - it may have less CA.

I notice the difference before I equalized the photos. Actually I only raised the 3100 image about a half stop. The raw images show a more dramatic difference than these JPEG's.

Again this isn't a big deal. As Paul says I think defringe will take care of it. It is a curious difference though.

Dave

 

[pinktank]

Is it possible to get a test of shift+rise combined to the edge/beyond the image circle on a wide angle, comparing the x80 and the 100mp backs? I have yet to see a well controlled test anywhere that is looking at the stitching potential. 60XL would be ideal (or 43xl)

Thanks!
d

 

[dougpeterson]

Is it possible to get a test of shift+rise combined to the edge/beyond the image circle on a wide angle, comparing the x80 and the 100mp backs? I have yet to see a well controlled test anywhere that is looking at the stitching potential. 60XL would be ideal (or 43xl)

Thanks!
d

Already done. Just haven't had time to organize/process/upload the test.

Email me and I can send you the raws relevant to your request here.

 

[Paul2660]

Is it possible to get a test of shift+rise combined to the edge/beyond the image circle on a wide angle, comparing the x80 and the 100mp backs? I have yet to see a well controlled test anywhere that is looking at the stitching potential. 60XL would be ideal (or 43xl)

Thanks!
d

You can get a lot of information here. Indoor test but plenty of images. Response is very similar to the 50MP back and recovery appears very good.

Paul C

https://captureintegration.com/phase-one-iq3-100mp-technical-camera-testing/

 

[ErikKaffehr]

Hi,

This may be a separate issue from what "Void" has seen. It may just be a problem of highlight recovery. Would I have the raw files I would look at the specular highlights and how each channels goes into/out of clipping.

It would be possible that the issue may be some kind of chromatic aberration. Lloyd Chambers has seen similar stuff on the Leica S, but he found out by accident that they were not visible when exposure was by white led. After that he found out that the effect could be eliminated by an IR cut of filter. (Or was it UV cut off?)

It may also be that it is caused by some "feature" of the CMOS sensor. It is not the same design that is used in IQ-250.

If you would be kind enough to share the raw images it would be most helpful.

Best regards
Erik

Here is what I mean about the highlights. I don't think this is any different that what others have shone before (Voidshatter's security camera). This is v9.0.3, and perhaps Phase will continue to make improvements.

Not that this is a deal killer, just something the 180 handles better. I agree it seems to be a CMOS thing. In general they seem more sensitive to purple. I'm sure there are 50 technical reasons why that is not the case, but it sure is my perception.

Dave

Edit: note that the 3100 image was even 1 stop under the 180 image. I matched exposure and color on the wall to the left. These are both 100% crops from the upper left of an image (40hr).

 

[dchew]

Erik,
Here is the link to the raw files:
https://www.hightail.com/download/ZWJYTGsrdzhrYUJvSWNUQw

When I originally made the switch from a Canon 5D to the IQ180, I felt the way the 180 handled this type of highlight was more natural. As you say, it could be several things. The exif data says it was a 2 sec exposure on the 180 and a 1 sec on the 3100. If anything the 180 image should be clipped more given the longer exposure and the lower DR. But as you know the recorded shutter speed on these backs is not all that accurate when using a copal shutter, so I can't say for sure the 180 image was longer. They were both set to ISO 100 and the same f-stop.

The lighting was difficult on purpose, but identical for both. In fact the lens flare was pretty close to identical in each shot. I used to refer to this purple fringing from saturated areas as "blooming", but I'm not sure that is the right term. I looked at a similar shot from the a7rII on a Batis 25. It handles this better than the 3100 but not as well as the 180. Again many different variables so who knows.

I will repeat this is more of a curiosity than any sort of "issue"; it just isn't that different to worry about. For me, the decision to upgrade will basically be 1) live view and 2) staying on the upgrade discount path vs. the cost of doing so. Very rarely do I want to shift/rise/stitch anything wider than my 60xl, and the 3100 seems to handle that just fine up to 18mm. And unlike Voidshatter I have no interest in very long exposures or in pushing shadows beyond minor adjustments. So (again for me) any upgrade will have nothing to do with image quality.

Dave

Hi,

This may be a separate issue from what "Void" has seen. It may just be a problem of highlight recovery. Would I have the raw files I would look at the specular highlights and how each channels goes into/out of clipping.

It would be possible that the issue may be some kind of chromatic aberration. Lloyd Chambers has seen similar stuff on the Leica S, but he found out by accident that they were not visible when exposure was by white led. After that he found out that the effect could be eliminated by an IR cut of filter. (Or was it UV cut off?)

It may also be that it is caused by some "feature" of the CMOS sensor. It is not the same design that is used in IQ-250.

If you would be kind enough to share the raw images it would be most helpful.

Best regards
Erik

 

[Paul2660]

Thanks for the links.

The highlight area, is actually very small at 100% view, and may not even be noticed, but it does easily clean up in LR, with the Definge tool. C1 can't really get it with the CA adjustment or the manual defringe slider.

The 380 does a good job on the subject, however the areas that immediately standout are the foreground lower corners, whee the 2 seats are, as you have no issues pulling up the shadows and keeping details on the CMOS shot. It's interesting to play around inside these files, to realize the great depth that both backs can give. Overall the 380 file looks great, until you open the 100MP file and look into spots of shadow, where the 380 starts to give up details. But to be fair to the 380, with C1 9.03 IMO the files are very close, assuming both were at base iso?

I see better details on the stereo, and the set of folders in the lower right corner and a bit more details on the horse painting.

Thanks for sharing.

Paul

 

[dchew]

... assuming both were at base iso?

Paul

Well, they were both at 100. I normally shoot the 180 at ISO 35. But I think 100 is considered the base ISO.

I agree with your analysis of the files. Although both files are darn good, the 3100 has more workability.

Dave

 

[ErikKaffehr]

Hi,

Thanks for the files!

I think it is a clipping issue. If you check the enclosed screen dumps you can see that IQ3-100MP has fewer clipped pixels in the red channel then in the other channels. The IQ-180 is almost perfectly balanced.

I guess this is caused by the IQ3-100MP having a different balance between sensivity on the blue and red channels compared to the IQ-180. The reason may be that the IQ3-100MP is more balanced for good performance in mixed (low colour temperature) light while the IQ-180 may be more balanced for daylight/strobe. Call it a guess or possibly an educated guess.

Best regards
Erik

Erik,
Here is the link to the raw files:
https://www.hightail.com/download/ZWJYTGsrdzhrYUJvSWNUQw

When I originally made the switch from a Canon 5D to the IQ180, I felt the way the 180 handled this type of highlight was more natural. As you say, it could be several things. The exif data says it was a 2 sec exposure on the 180 and a 1 sec on the 3100. If anything the 180 image should be clipped more given the longer exposure and the lower DR. But as you know the recorded shutter speed on these backs is not all that accurate when using a copal shutter, so I can't say for sure the 180 image was longer. They were both set to ISO 100 and the same f-stop.

The lighting was difficult on purpose, but identical for both. In fact the lens flare was pretty close to identical in each shot. I used to refer to this purple fringing from saturated areas as "blooming", but I'm not sure that is the right term. I looked at a similar shot from the a7rII on a Batis 25. It handles this better than the 3100 but not as well as the 180. Again many different variables so who knows.

I will repeat this is more of a curiosity than any sort of "issue"; it just isn't that different to worry about. For me, the decision to upgrade will basically be 1) live view and 2) staying on the upgrade discount path vs. the cost of doing so. Very rarely do I want to shift/rise/stitch anything wider than my 60xl, and the 3100 seems to handle that just fine up to 18mm. And unlike Voidshatter I have no interest in very long exposures or in pushing shadows beyond minor adjustments. So (again for me) any upgrade will have nothing to do with image quality.

Dave

 

[dchew]

Thanks for doing that Erik. It is interesting that the red channel looks almost identical in both. You say the red Chanel is less clipped, which I understand. But the y axis is scaled differently, so I think the red channels are very close between the backs.

However, the green and blue channels are almost a whole stop brighter in the 3100 file. Note the natural light from windows off to the right is a lot brighter in the 3100 file. Could be just clouds or a different sensitivity. The 180 file was the longer exposure.

Curious.

Dave