# Thread: How does Better Light calculate MP count?

1. ## How does Better Light calculate MP count?

There was some discussion in another thread today about Better Light scanning backs. Never having used one of these I looked at the product line and came away confused about how total MP count is determined.

For example, here is the description of the Model 6000E-HS.

"Model 6000E-HS — The economical solution for pro photographers, museums and art repro companies who are easing into digital capture. Native maximum resolution at 100% = 6000 x 8000 pixels. Maximum file size at 100% = 137 MB in 24-bit RGB (274 MB 48-bit). Price: \$9,495 with 2-year warranty."

Now, if you download the .pdf for product information the Model 6000E-HS is said to give a file size of 144 MP. The Model 6K-HS, which is also listed as 6000X8000 pixels, is said to give a file size of 216 MP.

Question, how do you get 144 MP and 216 MP from a scan of 6000X8000 pixels? I would have calculated this as 48 MP for both backs. Are the higher figures interpolated resolution?

Sandy King

2. ## Re: How does Better Light calculate MP count?

Originally Posted by sanking
There was some discussion in another thread today about Better Light scanning backs. Never having used one of these I looked at the product line and came away confused about how total MP count is determined.

For example, here is the description of the Model 6000E-HS.

"Model 6000E-HS — The economical solution for pro photographers, museums and art repro companies who are easing into digital capture. Native maximum resolution at 100% = 6000 x 8000 pixels. Maximum file size at 100% = 137 MB in 24-bit RGB (274 MB 48-bit). Price: \$9,495 with 2-year warranty."

Now, if you download the .pdf for product information the Model 6000E-HS is said to give a file size of 144 MP. The Model 6K-HS, which is also listed as 6000X8000 pixels, is said to give a file size of 216 MP.

Question, how do you get 144 MP and 216 MP from a scan of 6000X8000 pixels? I would have calculated this as 48 MP for both backs. Are the higher figures interpolated resolution?

Sandy King
i'm not entirely sure.. but i suspect they're compensating for the fact that each pixel is non-interpolated (there's no Bayer mosaic going on). You get more real detail at the pixel level compared to the rest of the digital cameras

3. ## Re: How does Better Light calculate MP count?

Sandy, from what I remember (always a scary concept) there is a JEDEC or other trade group standard for calculating MP ratings. On a scan back, they are (claimed) to be equivalent to 3x the raw resolution. Apparently this figure compensates for Bayer pattern "irregularities" in photosites vs. actual resolution.

4. ## Re: How does Better Light calculate MP count?

They're pulling the same marketing BS as Sigma did with their Foveon sensors, and tripling the effective MP count since each photosite location samples R, G, and B. But you're not going to get 3x the resolution from one of these backs as you would from a Bayer sensor with the same number of photosite locations. The real world gain is in the 25-50% range.

5. ## Re: How does Better Light calculate MP count?

Originally Posted by JeffKohn
They're pulling the same marketing BS as Sigma did with their Foveon sensors, and tripling the effective MP count since each photosite location samples R, G, and B. But you're not going to get 3x the resolution from one of these backs as you would from a Bayer sensor with the same number of photosite locations. The real world gain is in the 25-50% range.
That makes sense.

In the BL literature it is noted that at a print size of 20" X 26.7" the resolution would be 300 spi. Since the sensor size is 72mm X 96mm (2.8" X 3.78") a print that size represents about a 7X magnification, which suggests effective resolution of around 2000 ppi, which would only be about 40 lp/mm. That sounds low to me.

Sandy King

6. ## Re: How does Better Light calculate MP count?

Originally Posted by sanking
40 lp/mm. That sounds low to me.
Seriously... A flatbed scan of a negative could get near that at a substantially lower cost, and you could use an instantaneous exposure! Step up to a drum scan and there's no comparison. Especially at 8x10.

7. ## Re: How does Better Light calculate MP count?

Originally Posted by sanking
"Model 6000E-HS — The economical solution for pro photographers, museums and art repro companies who are easing into digital capture. Native maximum resolution at 100% = 6000 x 8000 pixels. Maximum file size at 100% = 137 MB in 24-bit RGB (274 MB 48-bit). Price: \$9,495 with 2-year warranty."

Now, if you download the .pdf for product information the Model 6000E-HS is said to give a file size of 144 MP. The Model 6K-HS, which is also listed as 6000X8000 pixels, is said to give a file size of 216 MP.

Question, how do you get 144 MP and 216 MP from a scan of 6000X8000 pixels? I would have calculated this as 48 MP for both backs. Are the higher figures interpolated resolution?
You seem to mix up the MB (Megabytes) in their specs with MP (Megapixels) - a 16 bit sensor line will deliver six times as many bytes as pixels (two bytes for each of three colours) of file size.

Sevo

8. ## Re: How does Better Light calculate MP count?

Originally Posted by Sevo
You seem to mix up the MB (Megabytes) in their specs with MP (Megapixels) - a 16 bit sensor line will deliver six times as many bytes as pixels (two bytes for each of three colours) of file size.

Sevo
The figures I cite are direct from Better Light literature. The 6000E-HS is said to give 6000X8000 pixels for a rating of 144 MP, with file size of 137MB in 8-bit, 274MB in 16-bit.

And this is said to give a file size of 20" X 26.7" at 300 ppi. That indicates resolution of about 2000 ppi, which is confirmed by the linear pixel count divided by size of the sensor (8000 ppi / 96mm (3.78"), which gives resolution of 2116 ppi, or just over 41 lp/mm.

Sandy King

9. ## Re: How does Better Light calculate MP count?

Originally Posted by sanking
The figures I cite are direct from Better Light literature. The 6000E-HS is said to give 6000X8000 pixels for a rating of 144 MP, with file size of 137MB in 8-bit, 274MB in 16-bit.
How old is that thing? If it is ancient, that (only superficially impressive) figure might be brutal fact. 6000x8000 are 48MP - but with multi-pass with offset scan line, many backs can do a multiple of their native scan line resolution if you have the patience. A 144MP colour image of 274MB uncompressed size would be true 80's 16-bit with 5 bit/channel - back in the late eighties that used to be state of the art (though I don't believe that they already had 6k scan lines back then). On the other hand, 274 is close enough to the 288MB file size of 48-bit 48MP images - if it is new, they are lying or their marketing has made a mess out of their figures...

10. ## Re: How does Better Light calculate MP count?

Megapixels aren't everything, even though it's far from state of the art, my Phase One Studio kit with it's lowly 9mp images still look amazing printed double truck.

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