Search

Entries in noise reduction (2)

Sunday
Jul102011

Olympus E-P3 JPG Image Quality

 

 

 

Compared to E-P2 new E-P3 has also a new sensor and new image processor. According to Olympus image quality has improved by one stop.

 


Above: E-P2, ISO 800, Camera JPG Standard, NR Normal, Extra sharpening in LR3. Below: E-P3, same settings, No extra sharpening. (100% crop, Zuiko D. 50mm 1:2 Macro @ F4.0).


I shot a series of JPG test images with both camera´s ”even” ISO settings. At base sensitivity there is naturally no difference in resolution. When sensitivity goes up, E-P3 becomes gradually better so that at ISO 1600 it corresponds to E-P2 ISO 800 or is slightly better. Actually E-P2 image had to be helped with an extra sharpening to bring it closer to E-P3. Noise or graininess is stronger in dark grays in E-P3 image. From this point of view Olympus claim is true.

As can be seen in these frames  E-P3 image shows a watercolor-like smearing where structure or definition runs out. E-P2 has graininess in those areas. This difference in character is evident through out all ISO settings. Depending on subject smearing may not be seen at all at low settings and E-P3´s images can be very brilliant. Obviously it is sort of brilliance, that´s the best description I know, that Olympus seems to be after here. At higher ISO settings smearing can become disturbing if also reds spread and shadows have blotchiness.

Anyway, personally I do not like this kind of way to render as I already mentioned while writing about M.Zuiko 12mm images. I think also that this effect removes E-P3´s superiority starting from ISO 3200. I hope Olympus will  change rendering to be more like before. Now Olympus has been too much after clean, smooth and sharp look. A prompt firmware update, please!

My result and opinions here are strictly true only for camera JPGs at default settings. You can tweak the settings but still the same trend stays. Resuts could have been very different for E-P3 if I had swithced NR off and sharpening to minimum and tweaked those in post processing. But doing so would only make JPG shooting pointless. JPG´s whole idea is to produce as ready images as possible.

There was no RAW converter profiled for E-P3 and that prevents us from going any closer to the real capabilities of E-P3 sensor. Below, as an example, the same E-P2 exposure as camera JPG and converted from RAW in Lightroom 3. It is possible to squeeze out even some more resolution with Lightroom. And then you can get more out of tonality, dynamic range and colors, which I have left out of this blog. I will come back to this subject when I get an E-P3 profiled RAW converter

-p-   

Above: E-P2, ISO 800, Camera JPG Standard, NR normal. Below: Same picture, RAW conversion in Lightroom 3. (100% crop, Zuiko D. 50mm 1:2.0 Macro @ F4.0)

Thursday
Apr162009

Nikon D3x: ISO 400 -> 1600

Here are two observations on Nikon D3x in dimmer light conditions. One is about image quality at high ISOs and the other about camera´s stability at slow shutter speeds, which are kind of connected issues.

D3x, AF-S Nikkor 200mm 1:2G @ f/2, ISO 400


ISO 400 - ISO 1600

I have been lately shooting using Nikon´s great Auto-ISO feature. Previously I was very disappointed with Canon´s  Auto-ISO version in 5D MkII. For me it´s totally useless. Nikon betters by giving user two sets of parameters: a setting for highest allowed ISO value and a setting for lowest allowed shutter speed. These two settings make Auto-ISO a really useful feature. For instance with a 85mm lens I set 1/125s as the slowest allowed shutter speed. That ensures sharp hand held images, and thus gives me the real benefit from D3x high resolution sensor. Auto-ISO works as should with every exposure mode setting, and ISO sensitivity is shown in the viewfinder all the time so that I can override automation when ever wanted.

Originally I considered D3x only as a studio and landscape camera. I was not expecting anything special from higher ISO values at all. Actually in Lappland while shooting landscapes I was afraid of going over ISO 200 to maximize quality.  Now Auto-ISO led me suddenly into using higher values than before. When I evaluated images I was positively surprised with the clean tight noise granularity in them. Actually I did not notice any visual difference with Canon 5D MkII look which I liked so much. 

Now I had to test also this issue to really see how these two cameras compare.

Test image pairs at ISO 400, 800 and 1600 can be found here. Those images should be downloaded into your own computer if you want to see them at 100% size. Test images contain Canon files scaled (107,7%) into Nikon size to show comparable same size prints.

These images are converted from RAW files. Both cameras had always equal ISO settings and all camera corrections set off. Lenses were Nikon 85mm/1.4 and Canon 85mm/1.2 LII respectively. Aperture was set at f/8. My chosen converter was Adobe Lightroom because that´s the one I always use. Noise Reduction settings were Luminance 0, Color 25. To bring out any possible differencies I had  Shapening settings at 50 / 0,5 / 50. I´m fully aware that there are tests like DxO Labs (dxomark.com) which say these cameras should not have similar sensitivities. My findings do not support that claim. Same Lightroom tonality settings gave almost same highlight values only Canon being slightly more ”sensitive”, but these highlight corrected pairs show Nikon as slightly lighter at 1/4 tone. So these cameras seem to have a little different tonal responses but in reality sensitivity differencies are buried into differencies in lens aperture calibration.

I find comparison pairs very similar. Nikon has a slightly smaller and tighter noise grain and shows also a slightly better detail. This difference is shown on screen but it is almost disappears in a print. Still, this is a very impressive result from Nikon when you consider how much better camera D3x was at ISO 100.

Disclaimer:

I also test converted Canon files with DPP and Nikon files with NX2. DPP gave a cleaner and tighter grain structure for 5D MkII which I knew from my previous experience. Nothing new there. For D3x it was more interesting with NX2 but I did not see any practical difference between it´s two converters. So, because for me DPP is a subpar converter in every other respect than slightly better grain and sharpness I did not go into a useless trouble of trying to get DPP images into same tonality and sharpness as Lightroom images. Outside of test images I´m not going to sacrifice the beauty that I like in my real world Canon shots for a little tighter grain by using DPP. If anyone wants to see the difference between Lightroom look and DPP look, it can be seen in my comparison between 5D and 5D MkII.

 

D3x, PC-E Micro Nikkor 85mm 1:2.8D @ 1/50s, f/2.8, ISO1600. Crop 100%.


Stability of shooting at slower shutter speeds

Another IMO thing that had to be solved by doing a little test was the stability of hand held shooting. Namely, when I started  testing D3x it felt as a very stable platform and shooting with it felt positively non shaking. Now I have done some shooting with 5D MkII again, and when I raised it to shoot it also felt very stable but in a totally different way than D3x. The moment of exposure with the whole feel of it is so different. Actually, now I don´t know which I prefer more. But my little test showed that my first hinch was in the right direction. During a longer series of images that are scaled in to same print size I think I can manage more sharp images in the average with D3x. The slower the shutter speed the better for Nikon comparatively. Each of my test shots is a sum of ten consecutive shots. (Ten shot aligned as Photoshop layers to give as tight pattern as possible, mode screen). Shutter speeds are 1/15s and 1/2s, lenses 85mm like above.

This almost equal result shows again the difficulty of ”testing”. If someone says that one top camera is better in hand and has better ergonomics than the other, I say hardly, you just think so. These are very personal preferences that are dependent on your physiology and previous experience.

-p-