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Rick M

An image problem I have never seen before. Help!

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Hello, and thanks for the help. I have an image situation I have never encountered before, and am completely baffled! (I’ve sent this same message to NAPP, Canon, and a couple other serious photo forums for answers, suggestions, opinions.)

 

I list two examples below (there are others) from the same shoot/day/time:

 

Image #2309: Canon 5D Mk. lll w/ 70-200mm f/2.8

Metadata 3324 x 1801 pixels @ 300 ppi, Jpeg untouched

File size: 707 KB!!!

How is that even possible?

I have viewed it at 200% and it is still sharp!

 

Image #2273: Same camera and lens as above

Metadata 5760 x 3640 pixels @ 300 ppi, jpeg untouched

File size: 918 KB!!!

Still sharp at 200%

BTW: Other images from the same shoot are fine.

Please help. Any suggestions are deeply appreciated.

Obviously, Alamy rejected the files as “too small.” But they’re not.

Thanks. Very much.

Cheers,

Rick

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3324x1801 native is just too small for Alamy at about 5.9MP.

5760x3640 is 20MP and isn't too small.

JPEGs of that compressed size wouldn't look sharp at 200%, not by my standards anyway. You must have downsized them. What software did you go through?

Edited by spacecadet

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Thanks, spacecadet. Good info, and fast, Appreciated. (I'm not a techie. I always thought "Tech" meant "Blah!" in some obscure foreign dialect. )

 

As for the #2301 image at 3324x1801 being too small , that's the one that started all this!

 

Zooming in to 200%, it is just beginning to soften! (NEC MultiSync PA272W monitor). Absolutely no pixelation or any other anomaly. Edge to edge. I can practically feel the racers' hearts beating! (Sorry about that.)

 

In a 707KB file??

 

And NO Photoshop?

 

Really? How? Am I missing something?

 

Is it okay and/or safe to send the image? Would that make things easier? I don't know how it would help, except to verify what I've said. But if it helps ...

 

Thanks again, spacecadet.

Rick

 

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Thanks, Roger. Highest resolution JPEGS always in the 5D. Wouldn't smaller images go all funky zoomed into 200%? And my file size is at 300ppi.

 

Rick

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Rick,

 

I'm a bit puzzled by your question.  Did you submit these and get the automatic reply of too small?   Normally, Alamy just bounces the files that are too small and not the entire submission.

 

A couple of points.

 

As far as I know, and I'm no expert, the 300 ppi  ( or dpi ) refers only to print standards and has nothing to do with file size or sharpness.  Only the actual pixel size matters.

 

Alamy requires a minimum uncompressed file size  ( not jpeg size ) of 17 MB.  Your smaller file,  3324 x 1801 pixels, gives 3324 x 1801 x 3 = 17,959,572 bytes or 18 MB, so I wouldn't think it would have been rejected for size.   ( length x width x 3 where the 3 is for each of the three RGB colors in each pixel ).

 

Is there any chance that you downsized the files before saving and uploading to Alamy?  Check the actual pixel dimensions of the image as submitted.

 

The file sizes you quoted for jpeg files are for compressed files, not the original file.  The size of the jpeg file will depend upon your compression setting and the nature of the subject in the photo.  A high compression setting  ( low number in Photoshop ) and a mostly blue sky might give a jpeg file size of only 50 KB, while a low compression setting of a scene with lots of fine detail like small branches might give a jpeg file size of 10 MB for the same number of pixels in the original file.

 

With my Canon 5D Mark II I've never seen an image that I'd call sharp at 200%, although they can be very good at 100%.

 

Robert

 

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Like others I am not really sure what this question is asking but:

 

Uncompressed size is all Alamy care about (as far as file sizes go - they obviously care about a whole list of technical quality measures)

 

and

 

It often surprises me after my workflow via TIFF how "small" in disk space terms a full quality JPEG can be. To me it's less of a surprise when a picture with lots of complex detail makes a large file but the JPEG algorithm is sometimes able to compress without significant quality loss by a huge amount.

 

John

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Rick, you say that all other images are fine. Still, I would suggest you to go through the image quality settings on the camera once or twice more. Strange how often a more or less obvious reason just occurs to one when going through once more. But the fact that all the other images were fine points in another direction, of course. Did you download the images in the same and proper way? Some software - especially in wifi - may reduce the image size and quality.

 

Did you shoot all the images using the same settings (M, Av or Tv) ? My only experience is with the 5DII - but could you by mistake have used a pre-programmed setting only for these two images (dial setting C1, etc - or pressed a button perhaps)?

 

Any other circumstances that were specific for these two shots and images, and not the rest, may lead you on the track.

 

Most photographers here shoot in RAW - unless a direct news upload in JPG is necessary from the spot. You could use a RAW and full JPG setting in the beginnng to get both.

 

- and yes, as said above, forget the DPI setting - this is only for the printing of the image.

 

Niels

Edited by Niels Quist

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First, sincere thanks to you all, lately Robert, John, and Niels. I'm serious. Thanks for your patience and, obviously, your tolerance.

As to your "head scratchings" about my question:

In short, it came from my (misplaced) print-based world and experience (editorial, advertising, personal) in which 300dpi is it. That's been my only barometer until now, thanks to you.

Yes, I shoot RAW/jpeg.

Yes, only the two small files were kicked out. The rest of the submissions passed.

The jpegs in question were shot on-assignment, 2012-15. Bicycle racing. I reopened and QC'd them after a (much appreciated) Alamy "Trending" alert for such sports. And it was there, after one particular event, right in the middle of all these healthy files, come ... what? Two files in particular. So I wrote to the Forum for my first post.

Niels, you hit it out of the park with your math example on how to measure an uncompressed jpeg size! That changes everything for me. I never knew.

Now I do.

I've had some experience with stock. Nothing like Alamy, even after so short a time.

Thanks again, for such informative and relevant responses.

Take care,

Rick

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