Resolution help Please

JBurt

I use two cameras when I'm shooting shows. Both Canon Rebels. A 300 and a 350xt. The 300 loads my Hi-rez jpgs at 180 dpi. My 350 is loading them at 72 dpi. My templates are setup at 180 dpi so, I would like to change the 350 default to load at 180. Mainly to decrease possible mistakes when processing and for print quality + speed of service.

I have looked in my manual and can't seem to find how to change the camera's download default. I'm sure it is a simple fix but I seem to be missing it.

Any help would be appreciated.

ziggy53

JBurt wrote:

I use two cameras when I'm shooting shows. Both Canon Rebels. A 300 and a 350xt. The 300 loads my Hi-rez jpgs at 180 dpi. My 350 is loading them at 72 dpi. My templates are setup at 180 dpi so, I would like to change the 350 default to load at 180. Mainly to decrease possible mistakes when processing and for print quality + speed of service.

I have looked in my manual and can't seem to find how to change the camera's download default. I'm sure it is a simple fix but I seem to be missing it.

Any help would be appreciated.

JBurt,

As far as I know, those settings are fixed in firmware for the cameras. I don't believe that the XT has the ability to change the dpi in-camera.

I think you can use IrfanView in batch mode to rapidly change the setting in the EXIF header of the file, once you copy the files to a PC (assuming a Windows computer.) If you shoot in RAW, you can have the RAW conversion software do the deed. There may be other software available as well, to accomplish the same thing.

Let me know if you wish me to investigate a software solution in more detail.

ziggy53

JBurt

ziggy53 wrote:

JBurt,

As far as I know, those settings are fixed in firmware for the cameras. I don't believe that the XT has the ability to change the dpi in-camera.

I think you can use IrfanView in batch mode to rapidly change the setting in the EXIF header of the file, once you copy the files to a PC (assuming a Windows computer.) If you shoot in RAW, you can have the RAW conversion software do the deed. There may be other software available as well, to accomplish the same thing.

Let me know if you wish me to investigate a software solution in more detail.

ziggy53

Ziggy, thanks for the answer. I guess that explains why I couldn't find it. I use PSP so converting is not a problem. Just an extra step for the 350. I wonder why the difference between the 300 and 350?
Thanks again.

cmason

Hmm, that seems odd to me, since PS indicates that the files from my XT are at 300 dpi?

JBurt

cmason wrote:

Hmm, that seems odd to me, since PS indicates that the files from my XT are at 300 dpi?

Hmmm... now that is interesting.

The hi-rez jpg Rebel 300 images are 3072 x 2048. They load at 180 dpi for a print size of 17.067" x 11.378".
The 350xt images are 3456 x 2304. (the difference in sensor size) Hi-rez jpgs load @ 72 dpi for a 48" x 32" print.

I know I can convert in PSP. It just seems odd that there is a difference in download specs between the two cameras and no in-camera adjustments available.

I'm shooting a 250+ car show Saturday using both cameras. (2 points of entry) We shoot each car, process, and print onsite in a 7 hour period. (5 different size/types of prints) Any steps I can eliminate is a real plus. For instance, printing at 180 dpi instead of 72 allows me to cut individual print times in half while retaining acceptable quality. I shoot Hi-rez jpg for the standard prints and RAW for any specialty shots later.

claudermilk

You do realize that's a pointless setting until you actually print? It doesn't matter what the camera writes in there since the pixel count is constant. I'll check to make sure my output ppi is sufficient based on the pixel dimensions vs the desired print size, but as long as it's over about 180ppi I let it fall where it will.

JBurt

claudermilk wrote:

You do realize that's a pointless setting until you actually print? It doesn't matter what the camera writes in there since the pixel count is constant. I'll check to make sure my output ppi is sufficient based on the pixel dimensions vs the desired print size, but as long as it's over about 180ppi I let it fall where it will.

Yes, I'm aware of that. However, if I simply resize for an 8x10 print and the DPI remains at 72, when I put it in my 180 dpi template, I lose print quality on the 72 dpi portion. Unless, of course, I increase the printer's print quality which doubles the print output time.
Been there, done that in the middle of a show. I had previously only used the XT for RAW and didin't realize what was happening with the jpg's. It is not a happy experience.

I know the changes I need to make in the computers and printers. I'm just trying to save my people mouse/keyboard clicks as they take time.

ivar

JBurt wrote:

Yes, I'm aware of that. However, if I simply resize for an 8x10 print and the DPI remains at 72, when I put it in my 180 dpi template, I lose print quality on the 72 dpi portion. Unless, of course, I increase the printer's print quality which doubles the print output time.
Been there, done that in the middle of a show. I had previously only used the XT for RAW and didin't realize what was happening with the jpg's. It is not a happy experience.

I know the changes I need to make in the computers and printers. I'm just trying to save my people mouse/keyboard clicks as they take time.

I'm not understanding. I have no idea what dpi i take photos at, nor do i know how to change or set it somewhere.

When i want to print a photo at a certain width/height, how is the dpi important to me? I always thought that as long as i have a reasonable sized file (reasonable pixelcount) it didn't matter?

What am i missing?

JBurt

ivar wrote:

I'm not understanding. I have no idea what dpi i take photos at, nor do i know how to change or set it somewhere.

When i want to print a photo at a certain width/height, how is the dpi important to me? I always thought that as long as i have a reasonable sized file (reasonable pixelcount) it didn't matter?

What am i missing?

There is a difference in the quality of a print based on printer output. I have a premade template I use for carshows I put the picture of the car into. I use Epson printers which allow me to select print quality. Using a dpi of 180 allows me to print at twice the speed and comparable quality. I am talking 3 sizes. 5x7, 8x10, and 12x18.
If I use the car image downloaded at 72dpi and don't convert it to 180dpi on resize, that part of the print is noticably deteriorated. (you don't see it on the computer screen) I have to increase the printer's print quality from "Photo" to "Best Photo" which doubles the print time. By changing the original photo dpi to 180 when I resize to the desired size, I can print at a faster speed and retain an acceptable quality. A compromise, yes, but an acceptable one considering time constraints.

My Rebel 300 downloads at 180dpi by default. My 350xt doesn't.

I found the problem while at a show. Believe me, that is not where you want to run into something like this. :uhoh

The only time this is a problem is when we have 2 points of entry so we have to have 2 photographers shooting at the same time. Normally, I would just use the 300 for those images.

Edit to show a sample of what I print at a show:

gtc

raw conversion
i shoot in raw and when converting to jpegs i set it at 300 pixels per inch in the raw converter

Sam

I have CS2, and looked under the preference menu, units, and rulers, and there are two options under "new document preset resolution" One is for print resolution, and one is for screen resolution. The numbers can be changed. I am not sure if this applies only to new documents created in CS2, or if it will affect new documents opened from bridge.

Sam

JBurt

Thanks
Thank You Everyone for your input. It is much appreciated.

Art Scott

My camera also shoots at 72 dpi but when I run them thru ACR in PSCS it is automatically changed to 300dpi.......

I thought all DSLR's and pro-sumer digicams (Like the Konica-Minolta A2) all had default settings of 72dpi for speed of shooting and saving memory.

Steve Cavigliano

ivar wrote:

I'm not understanding. I have no idea what dpi i take photos at, nor do i know how to change or set it somewhere.

When i want to print a photo at a certain width/height, how is the dpi important to me? I always thought that as long as i have a reasonable sized file (reasonable pixelcount) it didn't matter?

What am i missing?

Ivar,
You're not missing anything. As mentioned, dpi/ppi #'s out of the camera are meaningless. Most use 72ppi since that works well for presentation on today's monitors. As also mentioned, this only needs to be considered when printing. Still, not even all that much then. With the ability to up rez images, you can still get your 180dpi+ out of almost any image. Now if you plan to print a 3 foot by 4 foot shot from a 1mpxl crop, you may run into issues.

So yes you are correct. A reasonable sized file will allow you to use 180dpi or greater when printing. When not printing, all changing the ppi does is shrink or expand the image size on the monitor.

Steve

claudermilk

OK, I think I see where your question is coming from. So you are now pulling images from the two cameras shooting straight to JPG & out to a printer onsite--thus the default of 72ppi is gumming things up. Is that correct? What app are you printing from? I wonder is just setting up a simple action in PS would do the trick.

ivar

Steve Cavigliano wrote:

Ivar,
You're not missing anything. As mentioned, dpi/ppi #'s out of the camera are meaningless. Most use 72ppi since that works well for presentation on today's monitors. As also mentioned, this only needs to be considered when printing. Still, not even all that much then. With the ability to up rez images, you can still get your 180dpi+ out of almost any image. Now if you plan to print a 3 foot by 4 foot shot from a 1mpxl crop, you may run into issues.

So yes you are correct. A reasonable sized file will allow you to use 180dpi or greater when printing. When not printing, all changing the ppi does is shrink or expand the image size on the monitor.

Steve

Thanks Steve, I *think* i'm starting to understand (again?)

ziggy53

JBurt,

You mention you are using PSP (Paint Shop Pro), so I'm hoping it's PSP 8. Starting with this version, you have some automation available. I don't have PSP so I can't give specific ideas or directions.

I think it would be best to use your existing technique for the dRebel 300, and create a seperate 72dpi template to use with the XT images. You can use the "Image", "Resize" to resample the combined images to the desired 180dpi for printing. Hopefully you can use the automation capabilities of the software to make the process as painless as possible.

As other have mentioned, PhotoShop may be a better tool overall, mostly because the "Crop" tool can crop and resample at the same time, saving you considerable time.

Good luck,

ziggy53

ziggy53

I just noticed that, starting with version 3.98 (current), IrfanView has the ability to losslessly change the JPG indicated DPI:

"New lossless JPG dialog option: Set DPI value"

Considering that you can batch process, it should provide a very usable level of convenience and speed.

http://irfanview.com/

ziggy53

smhs.images

I have a few questions. I have a limited understanding of file size, pixels and resolution. What I need to know is if I have files that I scanned that are HUGE...
2446 x 3846 pixel dimensions
Resolution 96
3,983 kb file size
I know how to resize them in Photoshop CS but I want to be careful to keep the integrity of the file and still be able to get an 8x10 print without quality loss.
What I was going to do is raise the resoltion to 300dpi and lower the pixels to 800x1258 which lowers to file size to 193kb. Is this correct? Can I raise the resolution or does that cause quality loss?
thanks.

colourbox

Sam wrote:

I have CS2, and looked under the preference menu, units, and rulers, and there are two options under "new document preset resolution" One is for print resolution, and one is for screen resolution. The numbers can be changed. I am not sure if this applies only to new documents created in CS2, or if it will affect new documents opened from bridge.

A document opened from Bridge is existing, so it isn't new. I don't think the print resolution number will affect it. I think the print resolution number only affects the New dialog box.

The screen resolution number affects how close the rulers and image match real-world size when you use the View > Print Size command. You need to enter a real-world dpi, which is number of pixels wide or tall divided by screen height or width in inches. I don't know if it affects anything else.

smhs.images wrote:

I have a limited understanding of file size, pixels and resolution...
2446 x 3846 pixel dimensions
Resolution 96
3,983 kb file size
...What I was going to do is raise the resoltion to 300dpi and lower the pixels to 800x1258 which lowers to file size to 193kb. Is this correct? Can I raise the resolution or does that cause quality loss?

One technically correct way to do this is:
1. Choose Image > Image Size
2. Uncheck "Resample Image" (very important)
3. Change the short side to 8 inches
4. Now the resolution should be 305.75 dpi (2446 dots divided by 8 inches), which is good because it's a little more dpi than you need. That is the resolution after resizing without altering the actual data at all, just redistributing the same pixels over a smaller area.
5. If at this point you want to lower the resolution to 300dpi, check "Resample Image" and then change the resolution to 300dpi. This will throw out the extra data.

The catch with that is that if your scan doesn't match the 4:5 proportions of and 8x10 print, it either leaves white space or you have to crop it. If you're uploading to smugmug you can crop it online, or forget about the problem and let the buyer crop at purchase time.

If you absolutely need it to be exactly 8x10, skip all the above steps and just grab the crop tool, and up in the options bar enter 8 for Width and 10 for Height (if tall), enter 300 dpi for Resolution, drag your crop rectangle and press Enter. That crops to 8x10 and resamples to 300dpi in one step.

The file size is a whole other story. It depends on what format you saved it in and with what compression options. For smugmug the size will be whatever it is after you get it to size and save as JPEG at 10 compression.

smhs.images

colourbox wrote:

One technically correct way to do this is:
1. Choose Image > Image Size
2. Uncheck "Resample Image" (very important)
3. Change the short side to 8 inches
4. Now the resolution should be 305.75 dpi (2446 dots divided by 8 inches), which is good because it's a little more dpi than you need. That is the resolution after resizing without altering the actual data at all, just redistributing the same pixels over a smaller area.
5. If at this point you want to lower the resolution to 300dpi, check "Resample Image" and then change the resolution to 300dpi. This will throw out the extra data.

The catch with that is that if your scan doesn't match the 4:5 proportions of and 8x10 print, it either leaves white space or you have to crop it. If you're uploading to smugmug you can crop it online, or forget about the problem and let the buyer crop at purchase time.

If you absolutely need it to be exactly 8x10, skip all the above steps and just grab the crop tool, and up in the options bar enter 8 for Width and 10 for Height (if tall), enter 300 dpi for Resolution, drag your crop rectangle and press Enter. That crops to 8x10 and resamples to 300dpi in one step.

The file size is a whole other story. It depends on what format you saved it in and with what compression options. For smugmug the size will be whatever it is after you get it to size and save as JPEG at 10 compression.

Thanks for the tip on the resample image box, I didn't know that. I got all the rest of that down. My other concern is the file size is too big and needs to be decreased because it takes up to much space on my hard drive. This is my main reason for adjusting the file. I have it saved as a jpeg 9 compression but it is still too large. What I was doing was making the file smaller but doesn't work if I do it your way. Any other way of decreasing the file size and still being able to print large sizes?

smhs.images

smhs.images wrote:

Any other way of decreasing the file size and still being able to print large sizes?

I just did a test between jpeg 9-10-11-12... WOW. I figured out my own problem. I initially saved these files at 12. Thanks for the help.

claudermilk

Yep, no reason to save a JPG at 12. Read the Smugmug help regarding 12 vs 10. The catch to watch out for here is you are resaving the JPG multiple times, so forcing it to re-encode the file; this is how you start getting noticeable artifacts. I would suggest scanning into PS, then making all the sizing changes and save it once.

BTW, 3.9MB isn't that bad of a file size, my 20D CR2 files are 8MB each, and I know the 1D MkII's are at least 12MB each. I'm afraid to know what Leaf 45MP MF backs save as. :uhoh Storage is cheap, plan on getting more drive space as you take more photos (in a year I went from happy with 80GB to having nearly 1TB and planning on more soon).