Alamy rejection "Interpolated" but they weren't !?

Leica 35mm f/1.4 Summilux M Aspherical MF - Black

01/16/2007 08:27:24 PM · #1

I just got an Alamy QC test rejection email because my photos showed signs of interpolation - but they shouldn't have.

The photos were 8mp shots from a Sony DSC-F828 (decent camera). Upsized using Photoshop bicubic.

After the rejection I downloaded their suggested "Genuine Fractals" software and tried the upsizing with that instead - however, the result is more or less identical to the Photoshop Bicubic upsizing. I took a look at the actual pixels, and can't see a difference. Regardless, Photoshop bicubic upsizing should be more than adequate, so I'm thinking there must be something I'm overlooking?

What's the weak link here? Why are 8mp photos upsized through Photoshop showing "signs of interpolation" ?

Message edited by author 2007-01-16 20:27:36.

scarbrd

Leica M10

01/16/2007 08:35:15 PM · #2

Originally posted by rohanhill:

While the Sony DSC-F828 is a decent camera the sensor is relatively small compared to dSLRs. Cramming more megapixels onto a small sensor doesn't always mean better quality enlargements.

I suspect that this is where they are coming from.

01/16/2007 08:38:58 PM · #3

Originally posted by rohanhill:

Upsized using Photoshop bicubic.

could this be why?

Nikon AF Nikkor 85mm f/1.8D

01/16/2007 08:41:21 PM · #4

Any suggestions - are my images hopeless? I've got a lot of shots I'd really like to use.

Is it poor form to post an example on this forum for you guys to take a look at?

Louis

Nikon D800

01/16/2007 08:43:02 PM · #5

Originally posted by rohanhill:

Any suggestions - are my images hopeless? I've got a lot of shots I'd really like to use.

Is it poor form to post an example on this forum for you guys to take a look at?

Depends. Did you join DPC for the sole purpose of asking this question? :)

If you post, post a small thumbnail that's linked to the full-sized image.

01/16/2007 08:44:01 PM · #6

OK... some guesses in the dark:

Digital zoom in-camera?
JPEG quality set too low in camera?
8-megapixels from a P&S... quite possible is the cause
Bicubic resampling - maybe try Bicubic smoother, if using CS2.

01/16/2007 08:46:03 PM · #7

Originally posted by rohanhill:

Any suggestions - are my images hopeless? I've got a lot of shots I'd really like to use.

Is it poor form to post an example on this forum for you guys to take a look at?

You'll probably want to post links to images. Hopefully 100% crops for us to look at, so that we can see the details (or interpolation)

BTW, I see no problem in joining just to ask.

Nikon AF-S NIKKOR 24-70mm f/2.8G ED

01/16/2007 08:54:18 PM · #8

Hi,

Yes, I did just join to ask this question, I'm sure I'll be back though :)

Here's a link to a 100% crop of one of the images I shot at the same time as the submitted photos. This image has some other problems (chromatic aberation), but ignore them.

//www.rohanhill.com/example.jpg

Thanks for any help :)

thegrandwazoo

Nikon D750

01/16/2007 08:56:16 PM · #9

Originally posted by rohanhill:

chimericvisions

Canon EOS-60D

Canon EF 24-70 2.8L II

01/16/2007 09:01:30 PM · #10

Originally posted by rohanhill:

How about a 100% of one that you have upsized... the upsizing may be the issue.

01/16/2007 09:02:48 PM · #11

Originally posted by chimericvisions:

How about a 100% of one that you have upsized... the upsizing may be the issue.

Good idea.

01/16/2007 09:03:34 PM · #12

Sure,

//www.rohanhill.com/example2.jpg

Thanks again for the help

01/16/2007 09:04:04 PM · #13

I'm seeing jaggies around the pupil of the eye already. Not sure what it causing it, but it's definitely showing signs of pixelation.

01/16/2007 09:05:04 PM · #14

Rohan, does your camera have digital zoom?

01/16/2007 09:08:07 PM · #15

I believe it does, but I never have it enabled - and these photos were macro shots from 3 or 4 inches away anyway.

01/16/2007 09:09:13 PM · #16

It's not really a point and shoot either - although it's not a DSLR, its closer to an SLR than a point and shoot:

Sony F828

Message edited by author 2007-01-16 21:10:05.

Canon EF 17-40mm f/4L USM

01/16/2007 09:11:01 PM · #17

And yes, I see those jaggies in the original too - this is bothering me a lot now.

Ecce_Signum

Canon EOS-5D Mark II

01/16/2007 09:11:10 PM · #18

Originally posted by rohanhill:

I believe it does, but I never have it enabled - and these photos were macro shots from 3 or 4 inches away anyway.

Then surely we are not looking at a 100% crop? if you got a 640x?? of the 100% original we'd be looking at a very small area.

01/16/2007 09:11:29 PM · #19

Originally posted by fotomann_forever:

I'm seeing jaggies around the pupil of the eye already. Not sure what it causing it, but it's definitely showing signs of pixelation.

Yup, looks very obvious. I think that's why they got rejected.
Try re-sampling, like fotomann said.

01/16/2007 09:14:07 PM · #20

Originally posted by rohanhill:

And yes, I see those jaggies in the original too - this is bothering me a lot now.

If this is a 100% crop of the original out of the camera file. There's nothing that you are doing in Photoshop that's causing the problem. It's something in-camera.

Does this camera have a RAW mode?

Message edited by author 2007-01-16 21:15:44.

01/16/2007 09:21:04 PM · #21

Maybe I've misunderstood the 100% crop

The first example is a crop of a very small area of the original photo. It is a non-resampled image. In other words, the actual pixels in the first example, are the same actual pixels straight off the camera. (just not all 3200x2400 of them)

The second example is a small section of the resized image I submitted.

01/16/2007 09:21:39 PM · #22

i doubt the F828 would produce such crappy pixels on it's 100% crops.
please check if you had enabled some hyper in-camera sharpening or something? Also, if you could, check your RAW files (if you had shot them in RAW)

01/16/2007 09:24:50 PM · #23

I just took a look at some of the example photos taken with the camera on a review website. I see jaggies there as well - no? Maybe it's a camera thing.

//www.rohanhill.com/example3.jpg

01/16/2007 09:42:49 PM · #24

Here's a thought - I used a median filter on the original (1 pixel radius) and then did the upsize using bicubic smoother.

Think this would pass the QC test? Or are the images a lost cause?

//www.rohanhill.com/example4.jpg

Ya... I think it's a lost cause

Message edited by author 2007-01-16 21:43:10.