D700 and D4 post processing DPI reduction.

[Metalstorm77]

I have a D700 and a D4 and shoot both in RAW.
When I convert from RAW to JPEG files the resolution for the JPEG files are set to 300dpi
If I edit/cropped the converted JPEG files from the D700 and save, the final saved image will always returned to 300dpi.
However if I do the same with the JPEGs from my D4 my dpi will drop below 300dpi making the image look rather poor.
Frankly I don't know why this happens.
Anyone with any ideas? I'm all ears.

[Manfred M]

Nuttee - don't get at all hung up on DPI (Dots-per-Inch), as it does not affect anything. If you are finding image quality issues in your jpeg conversions, I would start looking somewhere else. Compression, sharpening, some quirk in the way that the PP software works, workflow, etc.

Where do you notice issues; on screen, at different magnifications, when you print, etc?

DPI "matters" if you are looking at creating a paper print, but even there, with modern printer driver algorithms take care of most issues, based on the native resolution of the printer in question. HP and Canon printers are 300 DPI, and Epson are 360 DPI, so in theory, if you work to the native printer resolution, there could be some theoretical advantages, but I've never noticed any in real life printing work.

[NorthernFocus]

As Manfred said, the dpi only matters when printing and maybe not even then depending on how the print job is configured.

What software are you using for your jpeg conversion?

[Metalstorm77]

Guys,

I have attached a picture taken with my D4. Noticed the sky is not a smooth blend of colour but grey streaks through it. Guess I'm trying to find reason(s) why screen quality looks so poor in some of the shots taken with my D4. When I know if I had taken the same shot with my D700 the blend of colours in this case would be much smoother. And now that you mentioned it and that I come to think of it, DPI is dots per inch and is related to printing. So it doesn't have anything to do with the imagine looking so unsmooth on computer screen.
I have gone and setup the D4 the same way as I have the D700 when I first purchase the D4. So they are identical in terms of HIGH ISO Noise reduction, compression of files...etc

Dan I use Photoshop CS5, Camera Raw 6.7 for Jpeg Conversion.

[AB26]

the sky is not a smooth blend of colour but grey streaks through it.

Nuttee,

Relax!
I almost flipped when I first saw the same thing happening with some of my images. I started GOOGLING and found that it has something to do with screen resolution and all that stuff. Nothing to do with the camera or poor image resolution.
It is something like, the screen cannot resolve the detail in the colour.

[Ido]

I'm not so familiar with the term and phenomenon, but I think it's called posterization, as can be seen in the image on the left here:


Just to clear things up: The image you posted above - was it shot in RAW or JPEG? I want to make sure I understand what it is before I give my judgement as to what might have happened here…

[Metalstorm77]

Andre...interesting. I use the same computer monitor to process photos from both cameras. I know that if I use my D700 to take the same shot the blend of colours will be much smoother. If it's the screen resolution I would have thought this would not be the case.

Ido. Picture is shot with D4 in RAW format post processed using PhotoshopCS5, Camera Raw 6.7. The RAW file is then converted to JPEG. The result is what you see.

[NorthernFocus]

What youu are experiencing sounds like "posterization". It is typically a jpeg artifact due to the 8bit image clipping subtle tonal changes. Nothing to do with the camera if you're shooting RAW. It is something in your workflow. Not enough info to help. Also post both images for comparison. Skies are notorious for this.

[Ido]

Ido. Picture is shot with D4 in RAW format post processed using PhotoshopCS5, Camera Raw 6.7. The RAW file is then converted to JPEG. The result is what you see.

It would be great, then, if you shared that RAW file with us for inspection. (We won't steal your photo. I won't, at least.)

[Mark von Kanel]

Hi Nuttee (how do you pronounce that name?) i Cant see any banding on your image at all. The image starts with a grey blue at the top and transitions smoothly to orange. nice image by the way! So im thinking its problems with you PC/monitor set up.

[Metalstorm77]

Cheers Guys,


Ido, I have no problems sharing the RAW files but how do I do this? On this website? Upload RAW files on here the same way I do JPEG?

Mark, the name can be split in two, for pronunciation, Nut-tee.

Dan, I'll read up on this "posterization" but still baffle why it appears to happen with only images from my D4. Weird.


Hopefully nice weather tomorrow so I can take a shot of the same scene with the D700 and D4 and post them so you can see the difference.

[revi]

One difference between the cameras is their pixel count, which means that the on screen images will be scaled by a different amount (to get the same size in pixels on screen). And the interpolation routines used for that must be fast, quality is probably secondary, which means that at certain scale factors you could get more artifacts.

[Metalstorm77]

One difference between the cameras is their pixel count, which means that the on screen images will be scaled by a different amount (to get the same size in pixels on screen)...

I did not give that a thought but it make sense to me.
My monitor resolution is 1920x1080 and the D700 resolution is (4256×2832) and D4 (4928×3280) so maybe some details are bound to be missed when convert to JPEG and display on screen.

[NorthernFocus]

I did not give that a thought but it make sense to me.
My monitor resolution is 1920x1080 and the D700 resolution is (4256×2832) and D4 (4928×3280) so maybe some details are bound to be missed when convert to JPEG and display on screen.

So your logic is that interpolating an image with more information available creates more artifacts than an image with less information available?

[Manfred M]

As a D800 shooter using a 1920 x 1280 screen I have never seen this type of artifacting in my normal workflow. My screen drivers don't seem to have any issues with the downsampling process.

I can create it by highly compressing jpegs and then trying to upsample and / or edit them. With RAW data, I see no way of getting blocked up images like the one you have shown.

[Ido]

Ido, I have no problems sharing the RAW files but how do I do this? On this website? Upload RAW files on here the same way I do JPEG?

No, that won't work.
If you use Dropbox or Google Drive, use that to share a link.
Otherwise, just Google for file uploading. Any website that lets you upload a PDF will probably let you upload a RAW file and keep it in the same uncompressed format.

[Metalstorm77]

QUOTE=NorthernFocus;426488]So your logic is that interpolating an image with more information available creates more artifacts than an image with less information available?[/QUOTE]

If you have a monitor that has a lower resolution than the pictures its trying to display. How does a monitor deals with the extra pixels? I was thinking, prehaps there is a lost of data in the down scaling. But is there?

[Metalstorm77]

As a D800 shooter using a 1920 x 1280 screen I have never seen this type of artifacting in my normal workflow. My screen drivers don't seem to have any issues with the downsampling process.

I can create it by highly compressing jpegs and then trying to upsample and / or edit them. With RAW data, I see no way of getting blocked up images like the one you have shown.

When you say "high compression jpegs" can you please explain how you do this if you use Photoshop. For me I just slide the scale bar from 1-12 to define my jpeg size.

[NorthernFocus]

If you have a monitor that has a lower resolution than the pictures its trying to display. How does a monitor deals with the extra pixels? I was thinking, prehaps there is a lost of data in the down scaling. But is there?

OK, here's a clue, does the problem show on your monitor when you open the RAW file in ACR? If no, then isn't it logical that it is not associated with the interpolation?

As a direct answer to your question, no, more available information (i.e. higher resolution, 16-bit, RAW format, etc.)always resolves better when reduced.

When you say "high compression jpegs" can you please explain how you do this if you use Photoshop. For me I just slide the scale bar from 1-12 to define my jpeg size.

The 1-12 scale defines the "quality" aka degree of compression of the jpeg. Try different settings without resizing the original file. For example if you save the full resolution image at a setting of 12, the file size in MB will be substantially larger than the same image saved at a setting of 1. The image size isn't different but the file size is different. Both images have the same number of pixels but the one saved at a setting of 1 is compressed much more and will have more artifacts. If you continue to modify jpegs, the information becomes more and more distorted with each compression routine and more artifacts result.

[Metalstorm77]

OK, here's a clue, does the problem show on your monitor when you open the RAW file in ACR? If no, then isn't it logical that it is not associated with the interpolation?

As a direct answer to your question, no, more available information (i.e. higher resolution, 16-bit, RAW format, etc.)always resolves better when reduced.


The 1-12 scale defines the "quality" aka degree of compression of the jpeg. Try different settings without resizing the original file. For example if you save the full resolution image at a setting of 12, the file size in MB will be substantially larger than the same image saved at a setting of 1. The image size isn't different but the file size is different. Both images have the same number of pixels but the one saved at a setting of 1 is compressed much more and will have more artifacts. If you continue to modify jpegs, the information becomes more and more distorted with each compression routine and more artifacts result.

if it was obvious maybe I would not have asked. Things aren't always what they appear to be hence I come online to save me a bit of time and ask questions from experts such as yourself and others.

Thanks for pointing out the 1-12 slide bar I'd realised it makes the files bigger or smaller but was unaware the pixels remains fixed.

Regardless I still can't pinpoint my issue so if anyone else has any other suggestions....go hard.