Have I been ripped off?

Just bought an SD1M and am disappointed with image size.

I was informed that the image size from the SD1M was 46mp.  That cannot be because when I take a jpg and display it to fill my 27" screen, it is at 77% enlargment

Nikon D800 at full screen is only 34% enlargement.

I also noticed the Sigma images are only 180 dpi whereas the Nikon ones are 300 dpi.

Am I doing something wrong here or is the advertising duff?

https://www.youtube.com/watch?v=DpGdLsG87qo

Funny. Do you have a serious answer?

You should return the camera. You don't understand the Foveon technology behind it. That's not necessarily your fault. It's a complex subject. But if you read the reviews of the camera you would understand the 15mp X 3 shorthand and what it means and you wouldn't have been surprised.

You should return it along with your new DPReview UserID.

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---> Kendall
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Thanks for the laugh!

People on this very forum have said the SD1M is equivalent to a 30mb Bayer camera. That is simply not true.

You apparently did not look at the pixel dimensions in the specs before you bought. The SD1M is 4800 x3200. The Nikon D800 is 7360 x 4912.

The SD1M has an APS-C size sensor. The Nikon D800 has a "full frame" size sensor (= 35mm film).

The Nikon D800 captures either red or green or blue at each pixel. Neighboring pixels are used to calculate an R,G,B triplet at each pixel. The SD1M captures the red light, the green light, and the blue light at each pixel (Foveon sensor).

No one of these specs, nor all of them together, tells you the image quality, which depends on the resolution, the color gradation from one pixel to the next, the dynamic range, and more.

General opinion is that at low ISO, the SD1M delivers better image quality than the D800. Some people say they are about the same. Fewer people say the D800 delivers better IQ.

No. You simply need to look deeper.

Have a look at the specs here and try to understand that the image dimensions are for a 15 MP 2D sensor - Now take those 2D dimensions and multiply them by 3. This is where all that extra image information is being stored. Get it?

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Regards,
Vitée
Capture all the light and colour!
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Ron,

Save yourself the trouble and return the camera. You'll be happier that way. If you want a bit more information on what a professional thinks, visit the Luminous Landscape and read the review there.

Please learn the difference between display pixel count and optical resolution.

Best regards,

LIn

--
learntomakeslidshows.net

I know that

I know that

I know that too.

None of that explains why the Sigma images are so small when compared to the D800 images. Nor does it explain why the Sigma images are processed at 180 dpi.

Is there a way to get the images to 300 dpi?

Ron,

What program do you do your post processing with?

Sigma software that came with the camera. I also tried converting the raw files to 16bit tiff and processed them in PS CS6

I'm not making a huge complaint. I'm just trying to work out why people say the SD1M is equivalent to 30mp Bayer cameras.

Got it. The short answer is because you can up sample the Foveon files 2x and (in general) not suffer image degradation. So shooting with the 15mpx3 DP camera will give you a print that will closely match a print from a 30MP bayer camera. If you use the Sigma software you can output at double size as a 16 bit tiff. Try that. Also, read the Luminous Landscape review.

There is too much hate in here.

Thank you. I've read the Luminous Landscape review and will battle on with this thing on my own. There is too much hatred in this group for me to feel comfortable here.

You're the only person who hasn't been hateful.

I'm happy to help. You just spent a good chunk of change on a camera. Stick with it. Did my reply above help? Try to output your images from SPP as "double size" images, change to 300 DPI in PS 6 (do not check bicubic interpolation) and see if you like those files.

HI Ron.

This has been an interesting thread, and I doubt that I will have much more to add, so if some guff follows, my apologies.

A quick answer first, for how to get both images displaying the same DPI. Use CS6 and re-size the image WITHOUT resampling it. Just change the DPI box to the same as the figure shown for the d800 files.

Now, rest assured you have not been "ripped off" as usually meant. You may have expected something different and that was not met. Part of any confusion would have to arise from the different way pixel count figures are used by different companies for their products.

I have an SD1M, as well as an original DP1 and DP2. In each case I just take their pixel counts as being 15MPx and 4.7 MPx respectively. Sure, you can make other comparisons to that will show some equivalence with other camera makes, one of which being the 30MPx equivalence - and under certain conditions - that you cited. I have been favourably impressed with all that these cameras can do compared to some of the others, and then in some cases not impressed by what they can't do. But that holds for anything.

I am interested in Foveon technology and that's what I got the cameras for. In addition, they stand up to much of what else is out there.

What you do with the camera is of course up to you, the advice offered so far notwithstanding. It depends on how you reconcile getting something you didn't expect.

Well, I see guff on the horizon, so that'll do for now.

atom14.

PS Ron: I just read your last couple of posts. I'm sorry you have not had a very good experience with some of the replies so far. There are lots more people in this Forum who I'm sure you would find to be quite helpful and friendly.

I haven't tried that yet. Have some family things to do right now, but will give it a shot this afternoon.

Overall, I'm quite happy with the camera. I knew it was going to be slow and I knew it was not going to be a point and shoot exercise. It's built quite well and doesn't have any creaks or loose bits.

I've only got 3 lenses for it at the moment (came as a job lot) and only one, the 50mm macro, seems up to the task. The other two - 17-70 and 70-300 are pretty ordinary to say the least.

Thank you again for being a voice of reason.