# Camera Resolution



## Silver Hawk

I consider myself fairly knowledgeable when it comes to photography but I couldn't understand why my photos were worse with my new Canon G6 7.0 meg pixel camera when compared with my 4.0 meg Canon A85.

The G6 was set to highest resolution (3072x2304) and highest compression (Super Fine), so what could be wrong?









Over the w/e, preparing for the Photo Competition (







), it dawned on me . It was the PC software I was using....I was using it to reduce these huge images down to roughly 800x600 and in doing so, the software was introducing lots of noise.

You can see this in the 2 images below. Both are taken from the same high resolution photo from the camera.

In the first one, the square gold line around the tank warning box is all broken and distorted; this image was greatly reduced on the PC. The whole image looks poor.

In the second image, there has been no reduction; this image is actual size and I've just clipped out the same box.

Moral of this is that if you don't plan to do extensive cropping of an image on your PC, then you should choose a resolution as close to the final desired image size as possible. In my case, I have 5 different settings and M3 or 1600x1200 is the closest.



















Cheers

Paul


----------



## pg tips

clever Paul, I've been shooting away at max res max size and didn't realise, I'll copy that to the hints and tips thread if you don't mind?


----------



## Roger

> and highest compression (Super Fine),


Paul,

With my Fuji ( 12Mp) , super fine is the least compression and is the same with a Sony that I have.

Roger


----------



## Silver Hawk

Roger said:


> and highest compression (Super Fine),
> 
> 
> 
> Paul,
> 
> With my Fuji ( 12Mp) , super fine is the least compression and is the same with a Sony that I have.
> 
> Roger
> 
> 
> 
> ←
> ​
Click to expand...

Roger ,

I quote from Canon manual on Compression:

Super Fine : High : Shot Higher Quality Images

Fine : Medium : Shoot Normal Quality Images

Normal : Normal : Shoot More Imagees

Paul


----------



## Wardy

Silver Hawk said:


> Roger said:
> 
> 
> 
> 
> 
> 
> and highest compression (Super Fine),
> 
> 
> 
> Paul,
> 
> With my Fuji ( 12Mp) , super fine is the least compression and is the same with a Sony that I have.
> 
> Roger
> 
> 
> 
> ←
> ​
> 
> Click to expand...
> 
> Roger ,
> 
> I quote from Canon manual on Compression:
> 
> Super Fine : High : Shot Higher Quality Images
> 
> Fine : Medium : Shoot Normal Quality Images
> 
> Normal : Normal : Shoot More Imagees
> 
> Paul
> 
> 
> 
> ←
> ​
Click to expand...

With the greatest respect Hawkey "Higher Quality Images" have the least amount of compression applied to them which is what I think Roger was trying to say (?)


----------



## Stan

Interesting point Paul, maybe the camera's compression algorithm is more capable that the editing software?

I'll give this a go with the 990 when I get some time, I'll shoot some pics at VGA and XVGA then resize the XVGA ones to VGA and compare them.

Shooting at target size for web work (maybe 800x600) would mean a lot less post production work and more pictures stored on a given card size.

Got be worth a try.


----------



## Silver Hawk

Wardy said:


> With the greatest respect Hawkey "Higher Quality Images" have the least amount of compression applied to them which is what I think Roger was trying to say (?)
> 
> 
> 
> ←
> ​










I've re-read the manual over and over...there are various tables in it....

Using 640 x 480 resolution as an example, the following file size are quoted depending on Compression setting

"Super Fine" = 249 Kbytes

"Fine" = 150 Kbytes

"Normal" = 84 Kbytes

...and they describe "Super Fine" as High Compression


----------



## Stan

I think the description in the manual is wrong Paul, lower file size is a result of _higher_ compression.


----------



## Silver Hawk

Stan









Wardy









Roger









I think it's me









In the Compression section, it has a "High <------> Low" scale. I had assumed they were referring to Compresion ratios but they must be referring to image quality. It's not very clear









So "Super Fine" = Larger File Size = Low Compression Ratio = Higher Quality Image. We all agree









But my original post on Resolution still stands, I believe.


----------



## Stan

Paul,

I think there is some milage in your theory, some software may be less capable at down sizing images than the camera is at taking them at a native compressed size.

This will vary between cameras and different computer software. What you have observed is that the compression algorithm in you camera's firmware is possibly better than your PC software's ability to maintain image quality when reducing a larger image size.

Most of us are used to working with printed images but as I've moved over to "screen" images I've seen as much need for consistancy and "working method" as I saw in my black and white darkroom days.

Any tip that might reduce the workload is certainly worth investigating.


----------



## mat

Stan said:


> This will vary between cameras and different computer software. What you have observed is that the compression algorithm in you camera's firmware is possibly better than your PC software's ability to maintain image quality when reducing a larger image size.
> 
> 
> 
> ←
> ​


This is it, your software looks to be using a simple 'nearest neighbour' algorithm, which doesn't do a very good job. Heres the image reduced with a bicubic algorithm










You could try one of these programs instead, but I'm not sure which, if any, would do a better job.

http://directory.google.com/Top/Computers/...aphics/Editors/


----------



## Silver Hawk

mat said:


> This is it, your software looks to be using a simple 'nearest neighbour' algorithm, which doesn't do a very good job. Heres the image reduced with a bicubic algorithm


Thanks Mat







. When you start talking about different graphic algorithms for image reduction, you've lost me, but as a software developer, I can certainly appreciate there are good routines and bad routines for doing specific things







Who remembers the different sorting algorithms? bubble sort etc. Some were very fast, while others were elegant.

I believe you have confirmed my principle that, if possible, you should avoid image reduction (or enlargement) on the desktop; all graphic manipulation software, no matter what algorithm is being used, *will* alter the image; after all, that's what the software is for! But in the case of image reduction, you hope it doesn't introduce other visible side-effects. In my case it has .... so







to Microsoft's Picture It....better dig out a copy of the GIMP









Cheers

Paul


----------



## Stan

I took two pictures on the Nikon Coolpix 990. One at 640x480 resolution and one at maximum resolution of 2048x1536, both on fine (lowest compression).

The 2048x1536 was resized to 640x480 using Paint Sop Pro v7.04 with no other manipulation.

At a zoom ratio of 4:1 it is possible to note a VERY slight improvement in sharpness in the native 640x480 shot but the difference is marginal.

In the case of the Coolpix and Paint Shop Pro combination I donâ€™t think it makes much difference which route I take. I might continue to shoot at maximum resolution/ minimum compression and resize in software for web work and have the advantage of a high resolution file in case I want to print it.

PSP seems to do a very good job of down sizing images, a pat on the back for Jasc Software I reckon.

640x480 original.










2048x1536 resized to 640x480.


----------



## Silver Hawk

Mmmm....I think your first shot (the 640x480 original) is clearly sharper....you've begun to loose the hatched font in the "Canon PowerShot" heading down in the bottom right hand corner...

But I agree PSP is making a pretty good job of it....

Tried out Mat's test using GIMP for Windows...you can stipulate which algorithm on an image reduction to use...and,







, Cubic is MUCH better.

Cheers

Paul


----------



## Roger

Hawkey,

I think there must me some confusion within the manual, as Wardy and others have said is fine...larger files mean less compression and less compression is good for quality ( usually)....If you are storing for posterity or important archiving ( precious family stuff?), I heartilly recommend taking the shot in .RAW format and storing on quality DVD/CD media. ( you can now buy high grade archival media now).

What is thr CR on the Hawk?? 6:1 ??

Roger


----------



## Stan

I like the Gimp too, it's very good indeed.









I resized the 2048x1536 to 640x480 using cubic mode in the Gimp just to see what happened. It looks very similar to the PSP effort to me.










Please bear in mind I may need new specs.


----------



## Silver Hawk

Roger said:


> What is thr CR on the Hawk?? 6:1 ??
> 
> 
> 
> ←
> ​


Roger,

Are you trying to confuse me?
















I assume you are now referring to the Compression Ratio on the Matchless Silver Hawk motorcycle ( otherwise known as the Matchless Model B ).

It is 6.1...how did you know that







? With a bore of 50.8mm (Std) and stroke of 73mm. Angle of cyclinders is 26 degrees.

Confused









Paul


----------



## Stan

Iâ€™ve been using my day off to experiment on resizing images because of this thread.
























Using PSP 7 as my standard Iâ€™ve worked out a method for basic reduction of image size for web use. Firstly Iâ€™ve turned off Jpeg compression on normal save operations.

I manipulated the images as required before resizing and finally adding unsharp mask as required before I saved the images but after I had resized them.

When resizing downwards I found that Bilinear resample seems to give best results and Bicubic resample works best for increasing image size.

When saving the image I went to export and adjusted the compression level to get the desired file size, obviously too much compression is going to introduce visible artefacts in the exported image so restraint is needed here.

This image was down sized from 2048x1536 to 800x600 using Bilinear resample but with out any compression introduced by PSP, itâ€™s quite a large file so it will take time to load.










The same image is on my website at 700x525 with compression to reduce the file size to just under 60kb to ensure quick page loading.

http://myweb.tiscali.co.uk/stanzplace/html...on_ventura.html

The diference can be seen if the images are saved and zoomed in on. Most of the artifacts in the second image are due to Jpeg compression.

Thanks Paul, this thread has made me do something useful on my day off instead of cleaning up.


----------



## Silver Hawk

Stan said:


> Thanks Paul, this thread has made me do something useful on my day off instead of cleaning up.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> ←
> ​


My pleasure Stan.









But I still maintain that if you know what size of final image you want, then set the camera resolution to the closest size with compression off. Image manipulation software should be banned.







When I was a lad, daguerreotypy was more than adequate.

You better get back to the other posted topics of the day --- your Red Rekord was mentioned


----------



## Stan

Sorry Paul, I must have missed the reference to the Rekord. Can you point me to it please?


----------



## pg tips

Stan said:


> Sorry Paul, I must have missed the reference to the Rekord. Can you point me to it please?
> 
> 
> 
> ←
> ​


 Where else Stan but in a thread entitled "Awful!!" I blame Jason


----------



## Stan

I couldn't find any reference to the Rekord in that thread, must be a mistake.









I'll look for a thread entitled "Awesome", that's where I'd expect to find a reference to the red Rekord.


----------



## jasonm

Stool Pigeon a cha cha cha .....


----------



## Roger

> It is 6.1...how did you know that


Hawkey,

A couple of decades as an active Biker and a couple of less active decades....it was one of the many scraps of ( seemingly) useless information that get stuck in the head....mind you, I cant remember the 710's birthday!!!

Roger


----------

