Wednesday, 22 December 2010

FujiFilm HS-10 - Raw Converters Compared (RFC and ACR) - Part Two

As a follow on from my previous post, below I am detailing the steps undertaken in a side by side comparison of the two converters - Raw File Converter (SilkyPix RFC, and supplied with the camera) and Adobe Camera Raw (ACR), which is part of Photoshop. It is also the development 'engine' used in Adobe Lightroom.

Part one is here

I wish to make it clear that I am not anti-ACR, far from it. In fact using Photoshop/ACR is my normal work flow routine, and I would much prefer to do all my work there.

That being said, I still come to the same conclusion. Simply, the supplied RFC gives a better overall result, for HS-10 Raw images.

My original summary, as published in part one, was :
  • Colour, tonal gradations, clarity are all better in RFC
  • RFC automatically corrects 'most' lens aberrations
  • Using the Lens Correction Module for the HS-10, in ACR, increases overall image softness

Anyway, follow through the steps below and I will explain why I see it that way. I would always encourage anyone to do their own comparisons though, and draw their own conclusions. Don't just take my word for it.

Note : The images shown here are all available in their original 'screen grab' size. Simply click the image

The RFC image is always at left and the ACR image at right.

1. The first step is to open the image in both converters simultaneously. The first thing I am doing here is to adjust the white balance so that each is similar to the other, and also so that the colours/tones are close to those of the original subject (camera).

As I have the camera sitting in front of me, it is quite easy to adjust the converter settings to match.

A couple of points to note :
  • The camera is not black. In fact it has a more charcoal appearance and has a very slight touch of tan to it. Neither converter portrays this quite accurately, despite my 'tweaking' any, and every, setting.
  • The buttons and lettering are the colours shown. The film label is most accurately depicted in the left hand image, except for the white lettering. This is more accurate in the right hand image.

Note : RFC does automatic lens correction for the HS-10 image. Accordingly, I also have the Lens Correction profile, for the HS-10, enabled in ACR. This would be a standard part of my work flow

2. Here, I am simply adjusting the sharpness and noise reduction settings. The objective is to get as much sharpness as possible, and without halo's or artifacts.

The objective with noise reduction is to eliminate as much Chroma (colour) noise as possible, and also to reduce Luminance (grain) noise. With the latter, the objective is to also try and reduce the noise without affecting the overall image clarity.

Overall, I wish to retain as much smoothness, with as much clarity, as possible. The final sharpening step, for either image, will be done later in Photoshop.

Note : In RFC the Sharpness and Noise Reduction (NR) menus do not show at the same time. I have pasted the NR menus here, for the sake of ease of explanation. Also, I need note that the NR engine within ACR, for Chroma (colour) noise reduction, is far more effective than the one in RFC. I tend to do my preliminary NR adjustments in NR, but keep the Chroma noise reduction low. I then adjust this further within ACR, prior to opening in Photoshop

Image view for both is at 66.7%.

3. With the sharpness and noise reduction settings applied, the next step is to tweak the settings slightly for contrast and clarity.

With the RFC image, I have simply adjusted the contrast slightly and raised the black point, also slightly. With the ACR image, I have increased contrast slightly and also increased clarity, quite a lot.

Image view for both is now at 100%

4. Within the actual converters, that is all I am going to do. Next step is to open both in Photoshop and inspect the images.

Here, both are opened and are being viewed at 66.67%

5. My next step is to sharpen both images, and by the exact same amount. For this, I use my own 'home grown' sharpening action - Details here

6. With that done it is quite apparent that the RFC image lacks some contrast. Here, I am simply increasing the contrast to get a closer match to the ACR image, and also to the subject itself.

7. With those steps done, I have now enlarged both images to 16 x 21.333 inches. This size is roughly equivalent to A2.

The reason for doing this is to see the integrity of the image, if it were to be printed at that size. This image won't be, but it is a simple way to show actual print size dimensions, rather than simply showing percentages of the original.

Overall, both look reasonably good, but I can see some areas where detail is lacking.

Note : There is some further information about screen dimensions and image sizing in another post - Click here

8. To get a much closer look, I have now increased the size of both images to 30 x 40 inches. This is exactly the same as if I were viewing the original images (not resized) at 100% view on my screen. My screen is correctly calibrated (actually all three are), so that exactly what I see is exactly what I would get, if printed.

Now, to get down to a little more comparative detail.

Note : This is called 'pixel peeping', and can be injurious to your health. Best not to do it, as it will drive you nuts !! Seriously, when editing, view an image just slightly above your intended output size. If it looks good, it will also look good printed. Typically, I view about 20% above my intended output size

Comparing both here, it is apparent that the RFC image is smoother and has better tonal transitions. The overall colour is also more accurate.

9. Still viewing at 30 x 40 inches, it is also apparent that the RFC image is sharper, and the ACR image lacks the smooth tonal transitions.

However, the white lettering on the ACR image is correct. It is a little 'muddy orange' on the RFC image.

10. Still at the 30 x 40 inches view, and looking at the detail around the viewfinder and control knob.

11. One thing that I cannot get any more detail from, with the ACR image, is the detail around the word FujiFilm, and certainly not from the logo. The logo is simply a blurred blob.

12. It could be argued that simply sharpening the ACR image will improve the overall result.

Well, here are the two images again, and as if viewed at 16 x 21.333 inches.

Both look quite reasonable at this size and, while the differences are there, they are not as glaringly obvious.

13. Now, let's do something silly.

Let's view the 16 x 21.333 images at 100% magnification. What this means is that we are viewing 16 inches x 300 pixels and 21.333 inches x 300 pixels.

My screen resolution is 96 pixels per inch (ppi). So, the math is this :

  • 16 x 300 = 4,800 pixels. 4,800 divided by 96 = 50
  • 21.333 x 300 = 6,399.9 pixels. 6,399.9 divided by 96 = 66.67
What this means is that in the examples below, we are actually looking at the images as if shown at a print size of 50 x 66.67 inches.

It is already apparent that the RFC image is smoother, yet has more clarity. The ACR image is already suffering some noise and showing sharpening artifacts.

14. So, simply to satisfy our curiousity, let's apply an unsharp mask (USM) setting of 250, 0.3, 0, and only to the ACR image. This is a fairly common USM setting.

Both images still look quite reasonable, at this size.

15. Now, let's go back to our silliness and view as if at 50 x 66.67 inches.

Not such a great idea !

There are obvious artifacts and halo's, and overall a general increase in noise in the ACR image. So, simply sharpening up the image is not the right answer.

Anyway, that's it.

I have drawn my own conclusions but, as I mentioned prior, and especially if you work in Raw with the HS-10, and you have Photoshop, or even Lightroom, do the comparisons for yourself.

Reality is that ACR does a very good job. I feel, however, that the RFC does it all just a little better.

Why ? I don't know - Does it really matter ?


Related post about using the Raw File Converter - Click here



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