Luminous Landscape Forum

Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: AJSJones on January 16, 2004, 03:06:55 pm

Title: Sony TRV 900 (no E) dpi
Post by: AJSJones on January 16, 2004, 03:06:55 pm
Don, Good NTSC video frames will be 640x480 pixels or so (i.e. 0.3 megapixels).  Not sure of how your camera captures stills but if you have gotten them into Photoshop the program will tell you.  When you capture images digitally, you capture pixels.  The number of pixels per inch varies depending on how big you a piece of paper you spread them out on (i.e. you don't capture at ppi - despite whay you were told!).  If you did nothing to your images except change the resolution to 300 dpi (under Image size type 300 into the resolution box and uncheck the "resample image" box) you would have a picture that is 640/300 inches by 480/300 inches - 2.1" by 1.6" - pretty small!  If the sensor in your camera is bigger, you might have e.g. 1024 x 768 pixels, not a whole lot bigger.  You should not expect high quality prints from this system unless you keep them small.  You can expand the file size by interpolation - after changing the resolution to 300 dpi, you can then type in new dimensions in the dimensions boxes and check the "resample image" box and the program will create new pixels from the existing ones. Note that it doesn't create new information but it will let you print a larger print but with lower actual resolution.  It sounds as though you have done something like this if your file sizes have gone up.  The 20MB images you refer to come from digital cameras with several megapixels (e.g. the Canon 10D has 6MP) and therefore have 10 to 20 times more pixels than your video!  Improving the quality of the image before printing it will depend on the original image quality, but you've come to the right place to learn about digital image manipulation so check out some of Michael's tips, essays and tutorials on this site - Instant Photoshop, Unsharp masking (USM) would be good places to look initially

Use the search tool to locate these or peruse the various sections and their istings

Good luck
Andy
Title: Sony TRV 900 (no E) dpi
Post by: DonG on January 16, 2004, 11:16:50 am
Hi

I took a lot of video of NYC in 2000 with my TRV900 and I am taking some of the still shots and clips from the video and printing them out.  According to the business that is printing them the dpi should be at 300.  When I go into photoshop, I can only deal with pixels per inch (ppi).  At least that's what I have found so far.  I was told that video is made at 72 dpi and cannot be increased (true or not).  I am able to increase the ppi to 300 in Photoshop as I convert to jpeg (printer takes tif also) whether that is doing anything at all, I don't know.  When I do this the file size increases to under 2 mgs whereas other files printed by company (not video), the size is 20+mgs.  My question, is whether I can increase the dpi or clarity of the photograph is a computer program after capturing it.  Thanks for any help that you can give.  I'm pretty sure that I used the camcorder at high quality position when videoing.

Sincerely

don

When you are at full resolution progressive scan mode, what is the dpi?