Just a question on mega-pixels

Bernie

Bernie

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David
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Ive noticed that when i download my pictures from my Camera's SD card onto my laptop and external hard drive then forward them on via email or any other program, that the problem is it has a extremely large file size. Is this down to the setting i have my camera on with regards the megapixels. Ive got it on 24 megapixel which is the highest, but from a review site it says this statement -

" 24 Megapixels is baloney; Nikon only added all the extra pixels to impress amateurs; no one needs any more than 3 to 6 megapixels for anything".
 
Sounds as if you are shooting in "raw" format and sending these versions. That is actually, for most situations, the best format to shoot in but normally, when sending or displaying, you'll usually convert to jpeg (small size files,etc.)

Come back with a little more information, camera, settings, etc. and we can enlighten you even further.
 
johnnypanic said:
Sounds as if you are shooting in "raw" format and sending these versions.
Click to expand...

Not necessarily. A 24 megapixel JPEG will be quite a large file.
 
Bernie said:
Ive noticed that when i download my pictures from my Camera's SD card onto my laptop and external hard drive then forward them on via email or any other program, that the problem is it has a extremely large file size. Is this down to the setting i have my camera on with regards the megapixels. Ive got it on 24 megapixel which is the highest, but from a review site it says this statement -

" 24 Megapixels is baloney; Nikon only added all the extra pixels to impress amateurs; no one needs any more than 3 to 6 megapixels for anything".
Click to expand...

I don't know where you got that quote from but it's baloney.

However, you need to understand what those massive files are useful for, and what they're not useful for.

They're for printing very large or allowing some cropping and still giving large prints.

So who are you emailing them to? What will they do with them?
 
Well, that statement is baloney; I'm dragging 60-80Mp detail out of 35mm film digitising it to pixels, before starting manipulations on it... but then again, I probably don't 'need' to have taken a photo in the first place.

As to your file-size? See:- "Understanding; Mega Pixels, Mega Bytes; tif, jpg, bmp, nef, & raw?"

Pixel count is just one of the variables that effect file-size. File size depends on how much data is used to describe the photo; more dots the pictures divided into, more data it will tend to need to describe it, BUT, the format, or language it's coded in has a big effect, then you have the question of compression, or whether the data file can be written in short-hand.

Reducing pixel resolution, is usually pretty sure fire way to reduce file-size; and for most 'screen-display' purposes, web-publishing etc; a PIXEL size of less than 5Mp is probably more than adequete; and for most general web-display, most sites will require pictures to be sized less than 1000px on the long side; ie less than 1Mp

BUT: for the most part I'd shoot at maximum camera resolution; to get the 'best' master image I could at point of capture; and then size down if needed for web-publishing or e-mail transmission after, in something like Photo-Shop.

You can always take data out if you have too much; harder to put detail in, if you didn't get it in the first place!
 
I think I know where that quote came from. If you say his name 5 times in front a mirror he materialises behind you like the candyman with a professional camera set only to jpeg. Is it Mr K Rockwell by any chance?

If you are sending them on try downsizing them to 1000ish pixels if they are just for viewing on a monitor and save them as a jpeg.
 
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Bernie said:
Is this down to the setting i have my camera on with regards the megapixels. Ive got it on 24 megapixel which is the highest
Click to expand...
Very probably. A 24 megapixel image will be a big file. And it's probably much bigger than the person to whom you are sending it needs.
Bernie said:
.... but from a review site it says this statement -

" 24 Megapixels is baloney; Nikon only added all the extra pixels to impress amateurs; no one needs any more than 3 to 6 megapixels for anything".
Click to expand...
Ah, that sounds like Ken Rockwell. It's a good idea to take what he says with a pinch of salt, because he often exaggerates for effect. In this case, there are professionals who need high megapixel counts, but there is more than a grain of truth in what he says. For example:
- standard image size on Facebook is less than 1 megapixel
- if you have a big HD TV, that's only about 2 megapixels
- you can make a print as big as you like with 6 megapixels, and it won't look pixellated from a normal viewing distance.

For 99% of people, 99% of the time, 24 megapixels is massive overkill.
 
johnnypanic said:
Sounds as if you are shooting in "raw" format and sending these versions. That is actually, for most situations, the best format to shoot in but normally, when sending or displaying, you'll usually convert to jpeg (small size files,etc.)

Come back with a little more information, camera, settings, etc. and we can enlighten you even further.
Click to expand...

Camera - Nikon D3200
setting - A - APERTURE PRIORITY
shooting in jpeg on 24 megapixel
 
Im certainly not using the file to print out, some of my files are emailed on to other sources, and ive been told there too high, im even noticing that some of my pictures are of item for sale, and the program wont entertain them due to file size too big.
 
Bernie said:
Camera - Nikon D3200
setting - A - APERTURE PRIORITY
shooting in jpeg on 24 megapixel
Click to expand...

Okay, forget what I said about raw format (although I'd still advise you to look into the advantages over jpeg).

If you're sending a full sized, full resolution, jpeg it will be quite large. You need to look at the image sizing, width & height as well as the ppi (pixels per inch). For example, to display on TP, you might resize to 1000 x 800 and 72 ppi. This will greatly reduce the file size, but would not be appropriate for printing, etc.
 
Bernie said:
Im certainly not using the file to print out, some of my files are emailed on to other sources, and ive been told there too high, im even noticing that some of my pictures are of item for sale, and the program wont entertain them due to file size too big.
Click to expand...
Nikon D3200? Well mine deliveres jpg at 6016x4000 pixels, and off camera file-size will be somewhere around the 9MegaByte size, give or take a meg or so.
You need to re-size in a photo-editor to reduce file-size.
If you use Photo-Shop or something similar, you will have options to reduce file size on 'save as' by adjusting the compression level.
Reducing compression level to perhaps 'Medium' can drop the file-size to about 1Mb, without reducing the pixel count.
You can reduce file-size more, by using re-size command and reducing the pixel count. Drop the long side from 6016 to 1000, and you'll get a file size at medium compression down around 300K
Its explained in link I provided.
Who are you sending pics to?
Who is rejecting or not accepting them?
What are you submitting them for?

Re-Shoot at lower camera resolution, lowest you can go on that camera is 6Mp; depending what the 'problem' actually is, that could still be too big to 'send' and need re-sizing in Photo-Editor

Help us help you, and we may be able to advice whether better to reduce file size by compression, or by reducing resolution.
Tell us what photo-editing software you have; we could probably even tell you how to do it.
 
One other factor (although I'm not saying it is in your case :)) is that noisy files tend to be larger with JPEG compression; they have greater entropy and consequently, there is less redundant information for the compression algorithm to throw away.
 
johnnypanic said:
You need to look at the image sizing, width & height as well as the ppi (pixels per inch). For example, to display on TP, you might resize to 1000 x 800 and 72 ppi. This will greatly reduce the file size, but would not be appropriate for printing, etc.
Click to expand...

Ignore the stuff about pixels per inch. Many people think it matters, but it doesn't.

Images that come out of your camera have a PPI number somewhere in the metadata, and you can change this with various software programs. But it means nothing. The only thing that really matters is the pixel dimensions.

Most computer monitors run at roughly 100 PPI, so an image which is 1000x800 pixels will display at about 10x8 inches on screen. An image which is 6000x4000, as yours are, will display at 60x40 inches which is much bigger than any monitor. You can't make it fit by changing the PPI setting in the image because the monitor is fixed at 100 PPI; you have to change the number of pixels. (And you can't display it on a huge TV screen either, because they have much lower PPI capabilities. For example a 42" HDTV runs at about 50 PPI.)
 
Teflon-Mike said:
Well, that statement is baloney; I'm dragging 60-80Mp detail out of 35mm film digitising it to pixels
Click to expand...

60-80MP from 35mm? I can pretty much guarantee that isn't all genuine information you're extracting, not even films like Adox 25 resolve that kind of detail!
 
That's right out the the Ken Cockwell book of quotes by the sound of it.

I export most of my photos to the web at ~8.5mp (Their taken at twice that) this allows a resolution that's good enough for full size display right up to a 4k screen.

In general no you don't need 24mp. This size is designed to allow cropping (taking a section and still retaining relative quality in the cropped section) I keep archived photos at full res because sometimes it's useful to be able to zoom in to a section.

For web and print then no they don't need to be anywhere near that size. Their are "tools" you can use to easily resize photos for web and e-mail.
 
PMN said:
60-80MP from 35mm? I can pretty much guarantee that isn't all genuine information you're extracting, not even films like Adox 25 resolve that kind of detail!
Click to expand...
No Idea what the film stock was without going back to the strips; probably Boots 100 CP
cs0014.jpg

Resized Full-Frame
cs0014C.jpg

100% Crop
Yeah... they're just about starting to pick out the grain; but only just. It's not until about 120Mp-ish that I'm starting to see pixels defining full chrystals.
Plenty of scope for cropping though, and they size down very nicely to display resolution.
 
Teflon-Mike said:
No Idea what the film stock was without going back to the strips; probably Boots 100 CP
cs0014.jpg

Resized Full-Frame
cs0014C.jpg

100% Crop
Yeah... they're just about starting to pick out the grain; but only just. It's not until about 120Mp-ish that I'm starting to see pixels defining full chrystals.
Plenty of scope for cropping though, and they size down very nicely to display resolution.
Click to expand...

IF there is no sharpness, what is the point of those all megapixels. 35mm film was never seriously intended for printing much over 10x8" - a tiny print really.
I don't care about all the pointless crystals, it is very soft and that is the end of it.
 
Teflon-Mike said:
No Idea what the film stock was without going back to the strips; probably Boots 100 CP

Resized Full-Frame

100% Crop
Yeah... they're just about starting to pick out the grain; but only just. It's not until about 120Mp-ish that I'm starting to see pixels defining full chrystals.
Plenty of scope for cropping though, and they size down very nicely to display resolution.
Click to expand...

That's not useful detail, it's a very soft crop.
 
I've turned down my megapixels to medium at 13.5 just to see how I go on
The thing that made me notice such a huge file is when I emailed a picture to a friend and it took forever and a day, the file under the emailed pic said 9842K whether that means anything.
 
daugirdas said:
IF there is no sharpness, what is the point of those all megapixels.
Click to expand...

Precisely this. The image is soft to start with so regardless of how high a resolution you scan with you're not extracting any more detail. Also the high resolution you're scanning at isn't likely to be native so you may as well just upscale the image in Photoshop, your scanning software is doing the same thing. Upscaling in PS will also fail to give you more actual detail.

Mike, you're being blinded by what you consider to be resolution and detail and completely neglecting the fundamentals. I've been drum scanning sharp 35mm images taken on all sorts of C-41 and E6 films over the last few months and the detail in your example isn't even close to what I can pull out at even 2000dpi (giving roughly a 6-7MP image).
 
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Bernie said:
I've turned down my megapixels to medium at 13.5 just to see how I go on
The thing that made me notice such a huge file is when I emailed a picture to a friend and it took forever and a day, the file under the emailed pic said 9842K whether that means anything.
Click to expand...

Is the emailed file the only use of these images?

Because the advice you've received is clearly to resize the images before you email. The only reason to turn the quality down in camera is when you're absolutely certain the image is as big as you'll ever need it and that you'll never want to crop it.

I have a cousin who's an idiot. When he got his first digital camera he thought he was a genius when he could make his camera fit 1000 images on his only card (instead of less than 100). Then he phoned me to say he couldn't get prints from his holiday photo's because they were only 800 pixels wide :bonk:
 
Bernie said:
I've turned down my megapixels to medium at 13.5 just to see how I go on
The thing that made me notice such a huge file is when I emailed a picture to a friend and it took forever and a day, the file under the emailed pic said 9842K whether that means anything.
Click to expand...

Yeah, it means that the picture has taken 9.8Mb of disc-space to store the pixel data. That's about right if camera is set to 24Mp 'Fine'.

If you read the Ken-Rockwell review; he reccomends 6Mp 'Normal' to get files around 700Kb.

The quality setting, 'Raw'; 'Fine'; 'Normal' & 'Basic' are setting the compression level; the Size setting the pixel count.

You'll find that using 'basic' at 24Mp probably gives a smaller file-size than 'fine' at 6Mp, curiousely.

As said, read tutorial I linked; explains how File-Size is related to Image-Size, and the effects of format and compression.

Whether you want to size and compress in camera or in photo-editor after, is up to you; but easier to dump data you don't need after you have cought it, than to find you haven't got enough to begin with,

PMN said:
Mike, you're being blinded by what you consider to be resolution and detail and completely neglecting the fundamentals.
Click to expand...

This is OT to OP.. and there's no up-scaling going on; wasn't explicit in description, as wasn't pertinent to OP; but the 'scan' was made from photographing original neg with D3200 in a slide-dupe lens & stitching sections. Takes 8+ sections to get enough over-lap to get accurate merge; resulting in a 60-70ish Mpix compiled frame, to work from. Resolution I'm getting is a feature of the process, rather than the object.... wish I could afford a drum scanner, but needs must!
 
Teflon-Mike said:
but the 'scan' was made from photographing original neg with D3200 in a slide-dupe lens & stitching sections. Takes 8+ sections to get enough over-lap to get accurate merge; resulting in a 60-70ish Mpix compiled frame, to work from. Resolution I'm getting is a feature of the process, rather than the object.... wish I could afford a drum scanner, but needs must!
Click to expand...

the scan is less than 1MP meaningful data and 59-69MP digital 'noise'. Sorry.
 
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