Olympus-OM
[Top] [All Lists]

[OM] Re: Scanning Query for you

Subject: [OM] Re: Scanning Query for you
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Tue, 01 Jan 2008 07:28:34 -0500
If the smaller files are 22.2 MB and all are the same size then the 
difference is caused by 8 bit vs 16 bit.  But, if the smaller files are 
of varying sizes then the difference is caused by compression.

Chuck Norcutt

Jan Steinman wrote:
>> From: "Jon Mitchell" <olympus@xxxxxxxxxxxxxx>
>>
>> Looking at the DNG files from my E330 (raw files, converted to dng  
>> with
>> adobe dng converter), they are coming in at 3136x2353 pixels (7.4MP).
>> With adobe rgb, 16 bits / channel, and 300ppi settings when I open  
>> them
>> in Photoshop.  The file size is around 18-20 MB.
> 
> Something wrong here. If you have two bytes per channel, and three  
> channels per colour, you should have 44.4 MB:
>       7.5 Megapixels times 3 (for R, G, and B channels) times 2 (for two  
> bytes per channel) = 44.4 Megabytes
> 
>> What am I missing here ?  How can 2 files with almost identical number
>> of pixels, same other details, etc., be so vastly different in size ?
> 
> 
> I suspect your first example is only one byte per channel.
> 
> :::: Those who don't understand UNIX are condemned to reinvent it,  
> poorly. -- Henry Spencer ::::
> :::: Jan Steinman http://www.Bytesmiths.com/Services ::::
> 
> 
> 
> 
> ==============================================
> List usage info:     http://www.zuikoholic.com
> List nannies:        olympusadmin@xxxxxxxxxx
> ==============================================
> 
> 
> 

==============================================
List usage info:     http://www.zuikoholic.com
List nannies:        olympusadmin@xxxxxxxxxx
==============================================

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz