Overcoming resizing hell?
 

Hi all

I'm currently using a Kodak easyshare compact!, some of the pics taken so far with this haven't been ''too'' bad (still just dabbling at this stage) however whenever I resize down to 800x800 pixels to upload in my gallery quite a lot of shots are rendered useless.

Is this just a result of using a cheap compact, or a natural process of resizing...will I still have this problem if I ever started using a DSLR?

Matt

Resizing downward will make your pictures better! If you imagine every picture with a number of flaws, when you resize downward to 800 x 800 to reduce the scale of the flaws along with the picture content. The picture content remains but every picture flaw is reduced.

To answer your question, your issue is not a consequence of a cheap compact but more the resizing algorithm being employed in your post production.

Can you show some examples.

Thanks, Canis Vulpes

Here's a couple of shots taken tonight

In both pictures the area around the branches has suffered some kind of distortion?, the originals in my folders look fine...

Matt

Hi Matt, I've looked at your thumbnails and the distortion you see in the branches appears to me to be "noise" from High ISO and the cameras own correction algorithm. To quote Ken Rockwell "Modern cameras use clever noise reduction which blurs the image in clever ways to hide noise. These systems are often clever enough to keep edges sharp. Unfortunately they blur soft details and textures along with the noise." I think this is what ahs happened in your case as you pushed the camera near it's limits.

Matt,

Can you give a fuller description of what you are doing please? Which software are you using to do this resizing? Which particular series of clicks are you going through to get the results you are doing? We may be able to help you a bit more if we have these details. I'd say you're using too high compression with jpeg images from the examples.

As Foxy has said, it should not be a result of using a compact camera, despite what Ken Rockwell would have you believe.

Regards,

Duncan

try this http://photoscape.en.softonic.com/
It's free... more info, once I've rembered how to use it (had it on the desktop previously). Unless you have something better already.

I'm not sure that I entirely agree with this... I've recently been struggling with downsizing images, they just seem to lack the impact of the full res shots. The loss of fine detail when downsizing can ruin a photo for me.

This is an interesting thread for me because I had trouble to start with and I now do all my resizes with Photoshop Elements. I aim for 480x360 pixels -sometimes I get away with 600x400 which seems to come in around 250 k - just under the site 300 k limit for uploads. If I tried 800x800 the upload would be rejected. How do others resize for uploads?

I second Duncan's request for info on how you are currently doing it Matt.

Until then, simple steps in Photoshop...

1. Select menu item Image->Image size...

2. Check the boxes "Constrain proportions" and "Resample Image".

3. Select "Bicubic Sharper" from the resample drop-down. I used to use Bilinear and then apply extra sharpening afterwards, but with CS2 and CS3 have used Bicubic for most web images and get favourable results with most images.

4. Type the width (or height) you want the longest edge in the relevant box at the top. For example, I would type 800 in width for a landscape orientated image.

5. Click OK :)

6. Apply a little sharpening (e.g. USM) only if it needs it...

7. Save as JPEG and adjust the quality to adjust the final file size (or save for web and adjust the quality to adjust the final file size.

Andy, try reducing the jpeg compression level, you will be surprised how little difference there is between a high quality and low quality jpeg when viewing on the screen.
600 x 400 shot should come in well below 250k (my 900 x 600 come in below 200 k most of the time).
I did a test a while ago by saving a 800 x 533 image in all the jpeg qualities between 4 and 10 and there was virtually no difference when viewing but the file sizes varied from 60k to over 200k.

I would go along with this all the way, especially item 7 about adjusting the quality to give you the desired file size - as stated in my previous post there is very little difference between a high and low jpeg quality when viewing (printing is a different ball game).

I never use 'save for web' as it strips the Exif.

Andy,

You aren't doing your pictures justice by using this method. Most members seem to have their screens set up to view pictures with a max width of 1024 pixels (landscape) or height of 800 (portrait). If your squeezing them down to 600x400 then people really won't be appreciating them at their best. Try resizing to the max dimensions I've given (depending on format) and varying the jpeg compression to about 70% of the max. As Roy says, it can make very little difference, but this depends on how complex the picture is.

This has been discussed at great length in several other threads.

Duncan

Thanks

To resize down to 800x600 pixels I simply use a free download tool from power toys plus?, downloaded it last year and never had cause to use anything else...I don't currently use any software from Photoshop.

I don't seem to have had ''too'' many of these problems with the last three images in my gallery.

Thanks for the responses everyone

Matt

There is an element of truth in what Foxy is saying if the original image is poor. i.e blurred. Generally the image will look sharper when down-sampled.

If the original is sharp then you are at the mercy of the re-sampling algorithm. Some are quick and dirty while others try to take into account what else maybe happening in that area of the image which entails more processing.

I am often accused of pixel peeping but I find it helps explain what is really happening. I've knock up a couple of simple images in Photoshop and down sampled them using a crude method and the bilinear method to compare against the original. The set in the top row are of a diagonal line with random noise added. The bottom set are just the line. The original was 480 x 480 pixels and down sampled to 233 x 233 pixels. The attached are 50 x 50 pixel crops blown up by 600%. In the crude method the resultant pixel is simply voted in or out by the majority. The bilinear method has dithered to retain some data instead of completely removing it. The dithering has caused a blurring hence the need for some degree of sharpening after the re-sampling.

The method outlined by Mark is tried and tested and gives good results.

Thanks all - I have always gone for highest quality jpegs - I'll use your advice from now on and maybe repost some of my images.

Andy,

If you don't want to lose any comments you have already received, you can use the "edit photo" link on the appropriate gallery image page and replace the original image with the resized one.

Duncan

Thanks Duncan, I found that button and have just replaced one or two images.
Andy M.

Hi Matt
Although I now have a digital SLR as well as a compact and Photoshop Elements 5 I still use the freebie Faststone for resizing my pictures.
I find that resizing down to 800 X 600 usually gives better results than resizing less !!!
Might be worth trying Faststone for cropping, resizing and sharpening as I do.
It's free & it might work for you.
Cheers : Ian Mc
PS Hi everyone from an expat Scot in Christchurch New Zealand.