coastal sunset panorama

Initially composed of 9 photos I think
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this produced a roughly 12000px wide image
cropped the excess edges down to 10500px
then this crop was at about 9000px
to get rid of the s bend in the horizon and improve composition
I worked all night on this, and im really quite proud of it
Watermarks there for posting other places where people arent so trustworthy
sad really, that I have to do that
Anyway
hope you enjoy it
http://maps.google.co.uk/?ie=UTF8&ll=53.521084,-3.06323&spn=0.001129,0.0...
centre of map is the exact position my tripod was
well, within 5metres

I've noticed that your images take much longer to download than almost anyone else's. I've just realised why. your images are 300 dpi whereas most are 72 dpi.

Can you do me a favour and post here at 72 please.

This image itself shows excellent colour, shame about the pipe in the foreground.

300DPI to 72DPI doesnt make a difference, and if it does, its roughly 40kb.
I know, the pipe is an annoyance, but I cant really do anything about it

300ppi and 72ppi are exactly the same when shown full size on screen, it's just that Rob tends to save his images at a higher quality level to preserve detail, so one of his 'normal' sized photos (say 800 x 530 pixels) might be 400kb, instead of 100kb someone else might save it at.

Of course, this panoramic is nearly 2000 x 600 pixels, and over 1.1Mb, so that's why it takes a while. But it wouldn't be any different if it were 300ppi or 72ppi.

Rob, I love the sky, and the sweep of the channel in the foreground, but there are a couple of bits (apart from that pipe) that spoil it a bit. When doing a panoramic like this, there's so much work going into it it's easy to miss bits.

First, there's a dust spot that shows up at least three times, near the top of the image. Secondly, there an odd bit in the sky just to the left and above the lefthand wind turbine. Lastly, there's a wobbly bit of horizon to the right of the turbines, and when you look down the picture from there, you can see the join's not so good here, unfortunately the pipe's practically pointing at it.

Overall it's a nice shot, but I'm sure you want to get it as good as you can, so hopefully won't mind me pointing these out.

Dan

As I understand it most monitors have a resolution of 72 dpi (I've seen 94 dpi mentioned somewhere), how then can a 300 dpi image show more detail on a 72dpi screen? Unless you zoom in of course, but if you have to zoom in to 'see' the picture properly, isn't that defeating the object?

it just seems to me to be making an image bigger for no reason.

If I'm missing something, please explain.

On doing a little research it seems that that there is little point in saving web images at 300 dpi unless they are downloadable for printing, but as ikillrockandroll is watermarking his images, he obviously doesn't want anyone printing his images, so why save them at 300 dpi?

If an image is saved at more than the screen resolution (usually 72 or 96ppi) then the computer can only show it at the lower resolution anyway, so there is no point in a higher resolution.

I think having this image so large is counter-productive, but only because it can't be viewed as one image anyway without excessive scrolling.

Thanks for the critiques guys
Daniel, I saw the odd bit by the turbines and sorted it (I think it was from a layer mask, i mustve caught my tablet with my pen when the brush was selected!", but the other two I didnt notice, its great you point them out because I was planning on getting this printed, so ill sort those on the large version Thanks!

And the image was imported as 300dpi simply because cameraraw does that; I dont save it especially as 300

There's a difference between dpi and ppi.

Dpi is 'dots per inch' and it's used when talking about printing resolution. An inkjet printer might have a resolution of 1200dpi, and this is how many individual dots of ink it can lay down per inch. Magazines and books are usually printed at around 300dpi.

Ppi is pixels per inch, and this refers to the image resolution when printed. In theory, the higher the ppi, the more detail can be shown, although this reaches its limit at around 300ppi.

If you have an image that is 1800 x 1200, and you print it at 300ppi the image would be 6" x 4". If you printed it at 100ppi it would be 18" x 12", but lower resolution, and could show pixelation. However, whatever the ppi was set to, when this image is shown full size on screen, it would always be the same size. If you save it at 300ppi, the monitor does not throw away unused pixels to show it at 72ppi, it simply shows it pixel per pixel. The resolution setting makes no difference.

Try it. Save the same image at different resolutions, but with the same pixel dimensions, then view it in a web page, it'll be the same size every time.

Rob's images are larger in file size (i.e. 400Kb, rather than 100Kb), because he'll choose Quality level 11 or 12 when saving the jpeg, rather than perhaps 6 or 7 or whatever.

Actually, here's a couple of demos:



300ppi



72ppi



Quality Level 12 - 231Kb



Quality Level 2 - 45.8Kb

They're all the same size on screen, but the first two have different ppi settings. The second two are saved at different quality levels, and the first one has more detail.

Dan

No problem Rob, when I did one of my first panoramas (back when I was scanning film to do them) I thought I'd done a great job, until about a week later I notice a tree which had a trunk that didn't match top to bottom. So easily done as you're staring at the pic for so long you start to miss bits.

I got some shots of these turbines back in the Autumn when I visited Formby Point to see the squirrels, not as good as this one though.

Dan

Thanks Dan, I was aware of that.

from the exif info of Rob's image.

Exif IFD1

* Compression = JPEG compression (6)

I'll take this to mean he used level six compression.

Well, sorry but I didn't realise, as from your original posts it didn't seem as though either you or John did. Dpi is not relevant to web images, ppi has no effect on file size, as shown in my example above.

Okay, well I didn't check on this particular image, it's probably safe to say it takes a long time to download because of its pixel dimensions. It's definitely not because of the ppi setting.

Perhaps Rob uses this quality setting on many of his pics, I don't know. I tend to use between 4 and 7, but try to keep the file size to around 100Kb, but sometimes it's more if the detail warrants it. Rob's just tend to be a lot more, so I would assume he generally uses a higher quality level.

Dan

To clear up any confusion, I saved it at 12
Next time i'll reduce it, I just like the high qualtiy
though saving at 10 reduces the file size by over a half sometimes.

Ahh yes, formby. Ill be going there for some shots when I buy a longer lens
Its interesting
All along this coast we have magnificent sunsets

And I doubt you'll notice much, if any, difference between 10 and 12, but it's up to you really. Perhaps you could put the note 'Large Image' in the title of the post so that those who don't want to wait don't view your post. Of course, they can always click the 'back' button if it's taking too long.

I do agree perhaps this image was a little wide to post here, not many people have a 2000 pixel wide monitor.

Dan