[barrymoir]

Hi folks

i was just curious as to how much of a crop you get away with on an image, for instance i took a photo of a couple of curlews today on the beach, got home went to process image and the birds were relativly small and distant within the picture, i took a crop at 800x600 just around the birds and was quite suprised at the qualiity and detail of the cropped image, it just got me thinking of how much can you get away with i.e area to crop from within an image.


Hope that makes sense, probably simple maths to work it out and something i should have known years ago.

[dazzajl]

Not much of an answer I know but the amount you can crop into a shot depends on how large you want the finished image to be, how big the original file is and how pure the shot is to start with, in terms of sharpness, exposure and noise.

I have had prints that look great off the 1D that are pushing on for an 80% increase in size from the original. Of course going the other way, I've taken shots that look lousy at the original size. As I'm sure we all have.

So it all comes down to suck it and see. If you can crop in to the part you want, enlarge to the size you need then it's all good. Wont happen every time though.

[CT]

You've discovered why birders pay thousands for BIG lenses. It's hard to fill the frame with little tits, if you know what I mean!

[Steve]

Originally Posted by CT

It's hard to fill the frame with little tits, if you know what I mean!

You'd get arrested here for that

If you are cropping for web use or low resolution/small prints you can be quite ruthless providing the original is a very good photo to start with. It's a sliding scale though, we all want the largest sensors and strive for cropping as little as possible to maintain the highest resolution and best quality.

[CT]

I've been playing with Genuine Fractals Pro for enlarging images. It's pretty impressive. Obviously, the sharper the image to start with the better, but it's excellent.

[barrymoir]

thanks folks, was just curiosity on my part.

[CriPPle]

With Genuine Fractals I have managed to print an A3 pic from a shot that started life at 1024x768. True it's not perfect if you get close to it, but a metre or further away and it looks nice and sharp.

Edit: oops just realised I made a mistake, the image I printed to A3 was 1280x1024 to start with.

[CT]

Originally Posted by CriPPle

With Genuine Fractals I have managed to print an A3 pic from a shot that started life at 1024x768. True it's not perfect if you get close to it, but a metre or further away and it looks nice and sharp.

Sam, do you follow their advice and increase in 5%, preferably 1% increments?

[CriPPle]

No I have only ever put in the final output size......I thought with gf you only had to do this, I thought it was only enlarging inside ps you had to increase slowly.

Thats something I'll have to go and read up, never really bothered reading the manual as I was very pleased with the results doing it like this anyway. The guy in the photolab didn't believe me when I told him how low resolution some of the images I was getting printed were.

[CT]

I read somewhere that even with GF the ultimate is to increase in 1% increments if you have the patience, for the best results. Since they claim you can go up to an 800% enlargement, that would be fun wouldn't it?

I haven't tried it yet either, and it's a new concept to me, but I'll have to give it a go.

[SammyC]

You would think they would automate that wouldn't you. Even if it took 20 mins at least you'd be able to wander off and have a cup of tea, water the plants and kick the dog etc whilst it did it!

[CriPPle]

I think tomorrow I will try making an action to do this and then give both ways a try to see the difference. Once I have finished I will post some samples for you to see.

[CT]

Good idea Sam. I'm not sure if you'll see an appreciable difference with web pics, but for that really big print....

[Gandhi]

I don't think that 'stair interpolation' is really relevant anymore, especially not with GF printpro. ASAIK it's designed to not have to do that now, mind you, I haven't read the manual yet either!

I think all this came from earlier versions of PS where the interpolation algorithms were pretty hopeless, an issue they addressed in CS2, and people needed to interpolate files for image libraries, obviously with minimal loss of quality. When I get back from work tommorrow I'll post some examples of stair interpolation with cs2 and GF printpro, and some without the steps.

From my point of view, I can barely tell the difference between GF printpro, PS's 'bicubic softer' and outputting at a higher than native resolution from Camera raw in ps!

[CriPPle]

Alright, been a bit busy over the last few days so have only just got around to sorting this out, but I have some examples of blowing up a picture by 20% using the two examples above.

None of the images have had any sharpening and are 100% crops

Original Shot


Increments of 1% Enlargement 20 times


Enlargement by 20% in 1 step


Enlargement by 400% in 1 step


I did not bother increasing using the 1% increments method due to the poor quality of the results from the first test.

These were enlarged with Genuine Fractals PrintPro 4.1

[CT]

LOL. I'd call that pretty conclusive Sam. Awful halos too on the step sharpened version.

[Warspite]

The patterning on the grass and the background is pretty bad aswell, definately proved conclusively which method is best

[Fangman]

Thanks for the examples - I always learn something from touring the posts.