Dynamic range of Sony sensor used in Pentax 645z et al

[voidshatter]

At least the 645Z is still top on the Claff PDR numbers. It's ashamed that the Canon 5DSR is still behind the Nikon D4s, though Magic Lantern firmware might make a huge difference.

[synn]

CCD backs have less dynamic range:

Psst.... Don't tell my Credo 40 that. It might start to think that it's not good enough to shoot the pcitures I want.

[Kolor-Pikker]

Psst.... Don't tell my Credo 40 that. It might start to think that it's not good enough to shoot the pcitures I want.

I remember when the selling point for CCD backs was their superior dynamic range at base ISO... and I remember it because it wasn't that long ago at all. People sure do get used to taking stuff for granted in the time it takes for them to learn said thing exists in the first place.

[mcbroomf]

Exposure bracketing is not ideal because there can be alignment issues. I have never seen anyone who can align my IQ260 files perfectly with reasonable effort: https://www.dropbox.com/sh/5i9dgi756x4yije/AABKcpNvQov8SFzbZuupv3E1a?dl=0

Misalignment between layers (due to vibration or filter etc) would cause drop of sharpness, hence defeating the purpose of pixel peeping with expensive digital backs. Why not just settle with a Nikon D800E/Canon 5DSR instead then? That's the main reason I dumped the IQ260.

I didn't have any trouble aligning your files using LR exporting to Photomatix, or letting PS align them.  What are you using?

[voidshatter]

I didn't have any trouble aligning your files using LR exporting to Photomatix, or letting PS align them.  What are you using?

I tried various things. Would you mind uploading your aligned psd file (with layers) to dropbox so I could take a look?

[mcbroomf]

I tried various things. Would you mind uploading your aligned psd file (with layers) to dropbox so I could take a look?

I can't figure out if Dropbox is loading it or not (never used it before and I don't see an icon but it says it has an hour to go, the file is 1.24GB).  I'll get back to it later today when I get back home.

In the mean time you can test what I did.  I opened the 2 image files in PS (exported from LR), then used File/Scripts/Load files into Stack, with Attempt to Automatically Align Source Images checked.

Again, what method are you using to align?

[voidshatter]

I can't figure out if Dropbox is loading it or not (never used it before and I don't see an icon but it says it has an hour to go, the file is 1.24GB).  I'll get back to it later today when I get back home.

In the mean time you can test what I did.  I opened the 2 image files in PS (exported from LR), then used File/Scripts/Load files into Stack, with Attempt to Automatically Align Source Images checked.

Again, what method are you using to align?

You could try other file hosting services, such like skydrive etc, if you don't mind?

Your method was the very first one I attempted and got frustrated I also tried professional software such like Helicon Focus etc but none did any good.

I have challenged on various forums and I have never seen a single person who can align these layers perfectly yet (with reasonable effort).

[mcbroomf]

You could try other file hosting services, such like skydrive etc, if you don't mind?

Your method was the very first one I attempted and got frustrated I also tried professional software such like Helicon Focus etc but none did any good.

I have challenged on various forums and I have never seen a single person who can align these layers perfectly yet (with reasonable effort).

I got it started before I left home (I found the icon and it confirmed an hour).  It had a while to go but I'll send it when I return.  I've used combinations of LR, PS and Photomatix for years to merge files with no alignment issues (using Canon before I switched to Sony, never MF though).

[mcbroomf]

I got it started before I left home (I found the icon and it confirmed an hour).  It had a while to go but I'll send it when I return.  I've used combinations of LR, PS and Photomatix for years to merge files with no alignment issues (using Canon before I switched to Sony, never MF though).

Try this

https://www.dropbox.com/s/v1bc24tci3f6h7v/CF002031_3_layers.tif?dl=0

[BernardLanguillier]

I remember when the selling point for CCD backs was their superior dynamic range at base ISO... and I remember it because it wasn't that long ago at all. People sure do get used to taking stuff for granted in the time it takes for them to learn said thing exists in the first place.

At that time the backs really were typically 1.5 stops DR better than your average Canon and this was pretty much seen as being worth 30,000 US$ for landscape shooters (yes, I know there are other reasons to use MFDB). This difference is significant because it makes it possible to under expose systematically images by one stop so as to protect highlights while still having shadows a bit cleaner. Many shooters were still trying to come to terms with the way digital handled highlights.

Remember the "BDs have 6 stop more DR than DSLRs" statement by a previous admin of this very site. This was a slightly exagerated expression of the perception of the importance of the DR advantage of backs.

We had enough resolution compared to a 645 piece of film, good enough colors, decent lenses, average bodies but still more than able to do the job as a light capturing box with a lens mount... DR was seen by many as the single most important shortcoming of digital photography for landscape/interior/architecture usage.

In the mean time Sony invented Exmor and de facto solved the DR problem better than the best CCD ever could and reduced the entry cost... from 30,000 US$ to a negative value compared to the Canon baseline. The good news being that you still can spend 25,000 US$ for an IQ250 if you need "the best".

Cheers,
Bernard

[ErikKaffehr]

Hi,

Wouldn't it be for that statement, I would never been interested in digital back. I could simply not get it. If the digital backs would have a 6 stop DR advantage, they should perform as well at 3200 ISO as a DSLR at 100 ISO. So I tried to figure out…

From what I know today, Bernard's assessment is essentially head on. MFDs had probably a 1.5 EV or so advantage over Canon, maybe even a bit more, at base ISO.

Now, traditional CCD based backs lag a bit behind the better CMOS implementation, according to all raw samples I have seen.

That said, MFDs can make gorgeous images, but so can DSLRs, specially when combined with excellent lenses.

Best regards
Erik

…
Remember the "BDs have 6 stop more DR than DSLRs" statement by a previous admin of this very site. This was a slightly exagerated expression of the perception of the importance of the DR advantage of backs.
…

Cheers,
Bernard

[voidshatter]

Try this

https://www.dropbox.com/s/v1bc24tci3f6h7v/CF002031_3_layers.tif?dl=0

Thanks for the effort! I have downloaded your layers and apparently these are far away from perfection - not even close to the previous challenger's attempt You would need to down-sample the picture below D810 size to make the misalignment less visible.

See below attached the misalignment at 100%:

[mcbroomf]

Thanks for the effort! I have downloaded your layers and apparently these are far away from perfection - not even close to the previous challenger's attempt You would need to down-sample the picture below D810 size to make the misalignment less visible.

See below attached the misalignment at 100%:

Yes, you're right, I was looking at only 1 place (which was well aligned).  I nudged the top layer until it was perfectly aligned on the right, but on the left it was still misaligned.  Same top vs bottom.  PS as I understand it doesn't just shift the layers, it distorts them to try to align the contrast lines across the image.  The high exposure of course is so massively exposed for the sky I wonder if it's lost the fine alignment lines it was using, they are certainly gone visually (I hope you understand what I'm saying).  I don't usually go anywhere near as high an exposure as this for my shadow layer.  I wonder if you've tried layering some lower exposure shadow files to your highlight files (but maybe that doesn't give you what you need).

Regards

[voidshatter]

Yes, you're right, I was looking at only 1 place (which was well aligned).  I nudged the top layer until it was perfectly aligned on the right, but on the left it was still misaligned.  Same top vs bottom.  PS as I understand it doesn't just shift the layers, it distorts them to try to align the contrast lines across the image.  The high exposure of course is so massively exposed for the sky I wonder if it's lost the fine alignment lines it was using, they are certainly gone visually (I hope you understand what I'm saying).  I don't usually go anywhere near as high an exposure as this for my shadow layer.  I wonder if you've tried layering some lower exposure shadow files to your highlight files (but maybe that doesn't give you what you need).

Regards

Imperfect exposures?  Then that means the success chance of a picture would rely on two independent shots - if either fails then the picture is ruined!  Have you ever experienced how nasty the CCD backs are when you need to wait for a darkframe NR countdown after each long exposure? It is simply *NOT* viable to bracket 3-5 exposures, not even for 2, because the light condition changes quickly during sunset / sunrise.

Okey, here is another example with less extreme exposures apart. Feel free to give it a try if the exposure satisfy your requirements: https://www.dropbox.com/sh/dnxwr7oneg8476m/AAB_GPD96eaZ3L0cmss4568Ja?dl=0

[mcbroomf]

Well I didn't say it was imperfect, I just said that the sky was so overexposed that it was blowing away the edges of the lines that I would assume PS is using to auto align, and that might be part of the problem.  I'm not sure, but the 2nd pair you uploaded, although not quite perfect are much better and the edges of the church roof are preserved. 

Any way, good luck, or just get a Sony 

[voidshatter]

Well I didn't say it was imperfect, I just said that the sky was so overexposed that it was blowing away the edges of the lines that I would assume PS is using to auto align, and that might be part of the problem.  I'm not sure, but the 2nd pair you uploaded, although not quite perfect are much better and the edges of the church roof are preserved. 

Any way, good luck, or just get a Sony 

Of course I use Sony CMOS  When I "upgraded" from the D800E to the IQ260 it was like a downgrade from a D90 to a D80 - very frustrating! CCD had its days and now it's time to let them rest in peace just like the films.