Image quality setting to display 1024 by 768 resolution on screen


rocketatw

Senior Member
Jan 15, 2010
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I am using a 7D, normally i will take my picture in 'L' image quality and resized to 1024x768 resolution.

I use jpeg, the image quality setting which i found on the manual stated

'L' - A2 or larger (59.4cm x 42cm)
'M' - around A3 paper size (42cm x 29cm)
'S' - aound A4 paper size ( 29.7cm x 21cm)

I open one of my jpeg file which is 1024 x 768 resolution and took the measurement,
it shows 38cm x 22.2cm, so can i safely say 'M' image quality is best for me? This question puzzle me as i usually set to 'L', thinking of setting to 'M' to save storage space but not sure will it compensate on the IQ of the image if i resized and display in 1024 x 768.
 

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Please read up about image resolution (dpi) for displays and for printing (if this applies to you). Also, do note that most photographers want to store the maximum amount of data for later post processing. The more you throw away by using lower quality settings the less you can do later with processing. JPG is a lossy compression algorithm, data which is not required (based on perceptive algorithm) will be deleted, irretrievable.
If you are worried about storage space I suggest a thorough scrutinizing of your images. It's better to delete 50 snapshots and keep 5 really good images in highest resolution, maybe even RAW format. Hard disk and memory cards are cheap.
 

rocketatw said:
I am using a 7D, normally i will take my picture in 'L' image quality and resized to 1024x768 resolution.

I use jpeg, the image quality setting which i found on the manual stated

'L' - A2 or larger (59.4cm x 42cm)
'M' - around A3 paper size (42cm x 29cm)
'S' - aound A4 paper size ( 29.7cm x 21cm)

I open one of my jpeg file which is 1024 x 768 resolution and took the measurement,
it shows 38cm x 22.2cm, so can i safely say 'M' image quality is best for me? This question puzzle me as i usually set to 'L', thinking of setting to 'M' to save storage space but not sure will it compensate on the IQ of the image if i resized and display in 1024 x 768.

I don't think you need to save HDD space to such an extent, do you?
After all, a 3.5" 500GB HDD costs well under $100, and you can store MANY photos on that :)
If you really only want to show your photos on your screen, with little or no post-processing done, I suppose M or even S is sufficient.
7D has quite high megapixel count. Even S size is larger than your typical 19" monitor's resolution. Easily more than sufficient for 4R printing.

But... as recommended, the RAW format allows more flexibility in post-processing, since it retains the most information from the original image. Better to have fewer but better photos than numerous snapshots.
 

M versus L just means the cam is down ressing image for you. With the usual hard disk size being at least 750gb today and storage per gb becoming much cheaper , suggest you store and shoot images at higher resolution since you will nv know.
 

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L = 5184 x 3456 = 17.9 megapixel
M = 3456 x 2304 = 7.9 megapixel
S = 2592 x 1728 = 4.5 megapixel
VGA = 1024 x 768 = 0.8 megapixel

You cannot convert pixels to length unless you know what your print or display resolution is.

The resolution of the prints at the labs is 300 dpi (ie dots per inch/pixel per inch)
This means at maximum print resolution of 300 dpi, L=12R, M= 8R, S = 6R, VGA <3R

The recommended sizes on the manual is based on around 200 dpi PRINT resolution which is regards as the minimum acceptable PRINT resolution before pixelation becomes obvious.

Your SCREEN resolution is 68dpi (based on your given measured dimensions). Any of the S, M and L resolutions are way above and adequate for VGA resolution. However, using lower resolutions would limit the quality and maximum size of any photos you may decided to PRINT in the future.

The quality of the images is also related to the compression ratio used. In the case of the 7D, I believe it only has NORMAL or FINE quality settings for JPEG. NORMAL = more jpeg compression than FINE.
 

thanks to all who reply.

actually i am not concern about hdd space, but i am concern about the storage space of the CF card, during oversea trip, i do have have a notebook with me, i only can pray hard my CF card dont run out, for you info i have 3 x 16gb and 2 x 8gb whenever i go for holiday.

just curious, if i take a picture in 'L','M' and 'S', then all resize to 1024 x768 resolution to display on the web. Will there be any different in image quality for the 3 image taken?
 

actually i am not concern about hdd space, but i am concern about the storage space of the CF card, during oversea trip, i do have have a notebook with me, i only can pray hard my CF card dont run out, for you info i have 3 x 16gb and 2 x 8gb whenever i go for holiday.
Be more selective. This amount of storage capacity would last me a loooong trip. In addition, if you have your notebook then create backup DVD's of your images.

just curious, if i take a picture in 'L','M' and 'S', then all resize to 1024 x768 resolution to display on the web. Will there be any different in image quality for the 3 image taken?
Unlikely. Feel free to try :) But as mentioned: the resizing to 1024x768 should be the last step in your post processing. Do keep the high resolution files safe. Once your image is down to display size additional steps of processing become visible, due to the nature of jpg.
 

rocketatw said:
thanks to all who reply.

actually i am not concern about hdd space, but i am concern about the storage space of the CF card, during oversea trip, i do have have a notebook with me, i only can pray hard my CF card dont run out, for you info i have 3 x 16gb and 2 x 8gb whenever i go for holiday.

just curious, if i take a picture in 'L','M' and 'S', then all resize to 1024 x768 resolution to display on the web. Will there be any different in image quality for the 3 image taken?

Oh my goodness...!
You have a total of 64GB of storage capacity on a holiday, and you're worried about running out of space? Are you serious? How long is your holiday? 6 months?

That is seriously A LOT of storage capacity...

I haven't done any tests on the various resolution settings you mentioned. I would assume that the difference would generally be imperceptible when resized to 1024 x 768.
 

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Oh my goodness...!
You have a total of 64GB of storage capacity on a holiday, and you're worried about running out of space? Are you serious? How long is your holiday? 6 months?

That is seriously A LOT of storage capacity...

I haven't done any tests on the various resolution settings you mentioned. I would assume that the difference would generally be imperceptible when resized to 1024 x 768.

haha, good question.

The answer is because i use video.:)