21mp Printing Limitations? And Cropping for Printing?

[ChrisAdval]

I have a 21mp DSLR, what are the limitations in printing?

I'm going to use adoramapix.com as my first time printing lab and these are the print sizes they offer

Kodak Professional Endura Supra Glossy

Wallets
Die Cut Wallets
Mini Wallets
3.5X5
4X5
4X6
4X12
5X5
5X7
6X9
6X18
8X10
8X12
8.5X11
9X12
10X10
10X15
10X13
11X14
11X17
12X12
12X18
10X20
16X20
20X24
20X30

Kodak Professional Endura Supra Lustre

WALLETS
DIE CUT WALLETS
MINI WALLETS
3.5X5
4X5
4X6
4X12
5X5
5X7
6X9
6X18
8X10
8X12
8.5X11
9X12
10X10
10X15
10X13
11X14
11X17
12X12
12X18
10X20
16X20
16X24
20X24
20X30
24X36

Kodak Professional Endura Supra Metallic

WALLETS
DIE CUT WALLETS
MINI WALLETS
3.5X5
4X5
4X6
4X12
5X5
5X7
6X9
6X18
8X10
8X12
8.5X11
9X12
10X10
10X15
10X13
11X14
11X17
12X12
12X18
10X20
16X20
16X24
20X24
20X30
24X36

True Black and White Paper (Matte Finish)

3.5X5
4X5
4X6
5X5
5X7
6X9
8X10
10X10
10X15
10X13

Kodak Professional Endura Supra Matte

WALLETS (X4)
DIE CUT WALLETS (X4)
MINI WALLETS (X8)
3.5X5
4X5
4X6
4X12
5X5
5X7
6X9
6X18
8X10
8X12
8.5X11
9X12
10X10
10X15
10X13
11X14
11X17
12X12
12X18
10X20
16X20
20X24
20X30

They're all about the same...

Also I know its best crop to the specific size but is it possible to still print without cropping on any of the above typical print sizes offered? Because some photos I really prefer the original un-cropped sizes than the print crops, i.e. 8x10.

[bigwater]

It is always best to resize your images to whatever specs desired in a dedicated image editing software program and then send them to print. Some online printing services have these features but in my own experience it hasn't worked as well. As far as the limitations on a 21mp camera most prints are done at 240ppi to 300ppi (points per inch also known as dpi or dots per inch) so for example I have a 15.1mp camera that captures 4752px (width) by 3168px (height) at 300 ppi that comes out to 15.84 in. by 10.56 in. at 240 ppi it comes out to 19.8 in. by 13.2 in. Not a perfect aspect ratio and some cropping is required but I think you can see that a 10/8 is much smaller than what is coming out of your camera.

If your in a big hurry and don't have time to learn the software their are companies and people out there who do that type of work for very little money myself included (no site yet but if you need help message me)

[OsmosisStudios]

Originally Posted by ChrisAdval

Also I know its best crop to the specific size but is it possible to still print without cropping on any of the above typical print sizes offered? Because some photos I really prefer the original un-cropped sizes than the print crops, i.e. 8x10.

Believe it or not, an 8x10 is cropped from the standard size. Your 21mp DSLR (a 5DmkII, I'd wager) shoots a 3:2 ratio. So any of the following is UNCROPPED. Everything else would have to be cropped somewhat.

2x3 (wallet)
4x6
6x9
8x12
10x15
12x18
20x30
24x36

[ChrisAdval]

Originally Posted by OsmosisStudios

Believe it or not, an 8x10 is cropped from the standard size. Your 21mp DSLR (a 5DmkII, I'd wager) shoots a 3:2 ratio. So any of the following is UNCROPPED. Everything else would have to be cropped somewhat.

2x3 (wallet)
4x6
6x9
8x12
10x15
12x18
20x30
24x36

I have a T2i/550D (crop censor) would that be any different than the full censor?

[OsmosisStudios]

Both are 2:3 ratio, so no difference. The crop sensor is exactly half, so it has the same ratio.

Your 550D/T2i is not 21mp though. It's 18.

[sk66]

To be picky; a 1.5/1.6 crop sensor isn't 1/2, it's more like .6666 (or 2/3). If it were half it would have a 2x factor.

[ChrisAdval]

Originally Posted by OsmosisStudios

Both are 2:3 ratio, so no difference. The crop sensor is exactly half, so it has the same ratio.

Your 550D/T2i is not 21mp though. It's 18.

opps sorry, so I follow that list above and don't need to do any cropping on that list and crop on others?

[OsmosisStudios]

Originally Posted by sk66

To be picky; a 1.5/1.6 crop sensor isn't 1/2, it's more like .6666 (or 2/3). If it were half it would have a 2x factor.

FX: 24x36mm
DX 18x24mm, roughly. Certain sensors vary slightly, but usually 15-18 x 23-25.

Exactly half, or very very close to it. m43 is half that: roughly 12x18mm.

Originally Posted by ChrisAdval

opps sorry, so I follow that list above and don't need to do any cropping on that list and crop on others?

Correct.

[sk66]

Originally Posted by OsmosisStudios

FX: 24x36mm
DX 18x24mm, roughly. Certain sensors vary slightly, but usually 15-18 x 23-25.

Exactly half, or very very close to it. m43 is half that: roughly 12x18mm.




Correct.

Kind of, but not really.
The error is it's "half" *if* you flip the orientation and only consider "square mm", but you can't do that. The difference is we are not talking "square mm", we are talking FOV/Perspective which is a characteristic of the sensor's diagonal measurement (which DX is 2/3 of FX).

Take a 100mm on a DX,it's 1.5x and it equals150mm FOV/perspective. To take 150mm on DX back to FX it's 2/3 (.67x).

[ChrisAdval]

thanks guys, is there a book that teaches this math to properly setup the images before sending them to a lab?