Going Digital - Maximum print size

[matt hedgecoe]

I am thinking of buying a 7D and have a couple of questions for you all...

 

What is the maximum 'acceptable' print size that you can get from a 7D?

 

I know this is a very subjective question as everyone will have a

different opinion of what is acceptable. As a frame of reference, at

present I mainly shoot on Fuji Velvia RVP50 and get cibachrome prints

of the best shots. At 15" x 10" (to my eyes) everything is razor

sharp. At 18" x 12" edges are just starting to soften.

 

The 7D manual says the maximum image size is 3008 x 2000 pixels. The

wisdom seems to be that you need 300dpi for a 'photo' quality print. I

make that a maximum print size of 10" x 6 1/2".

 

Is this really as big as you can go. I never trust the textbooks and

would rather listen to the opinions of people who actually use the

thing as it seems there is a lot more to image quality that just the

number of pixels.

 

What would you say the maximim size print is?

 

Thanks for any comments.

 

Matt

[mike_koenig3]

I've had a 7D for a year now and love it. Last August, we did a family photo shoot on a Lake Michigan beach. One of those photos was of me and my 5 siblings. My parents didn't have any photo of all of us as adults, so I had a professional lab make an enlargement and had it framed as a gift for Christmas.

 

I had to crop quite a lot from the original that was shot in landscape mode, as I turned it into a portrait shot. The lab told me that had I cropped it to begin with, a 16 x 20 would have been quite nice, but since I cropped it, 11 x 14 was their recommendation. It was tack sharp and made a wonderful print. They printed a sample of teh 16 x 20, and to be quite honest, I thought it was acceptable, although there was some pixelation (is that a word?). Based on their comments and my conversation with them, they told me that they routinely print 16x20 prints from 6 megapixel images.

 

I shot the image in raw format, converted to tiff using Capture One, and did some slight work in Photoshop. I'm not sure what tools they used, but I know that they started with my TIFF image. The photo was taken using the km 70-210mm F4 zoom, at about 120mm, ISO 100, 1/500 shutter.

 

This was my first enlargement beyond what I can do with my R800 printer and it was quite impressive. I had the same concerns before buying my 7D, but not any longer.

 

Great camera!

...

Mike<div></div>

[SCL]

It is highly dependent on the viewing distance. There have been billboard sized prints made which looked just fine at the proper viewing distance.

[mike_koenig3]

Good point. Viewing distance was also a part of my discussion with the lab that I used. In my case, this print would be viewed most often from a distance 2-4 feet.

...

Mike

[rdkirk]

You will have to interpolate ("upsample") to gain 300 dpi at print sizes beyond the "native" size that the camera's RAW image converts to TIFF or JPEG.

 

Presuming little or no cropping (which of course is an unknown variable) I find that it's most dependent on the subject matter. Interpolation ("upsampling"--using an algorithm to add pixels beyond the image's "native" size) works very well on subjects that are of low enough desired resolution that the image contains all the detail we need or want. The interpolation algorithms don't have much problem replicating pixels to "fill in the blanks" between pixels that exist in the image.

 

So portraits with fairly large head sizes tend to upsample very well because the image already contains all the detail we want to see--it's not hard for the algorithm to create additional skin pixels or additional dark pixels along an eyelash. We don't really care if it fails to create new pores or dandruff flakes that were too tiny to be resolved on the original image.

 

Interpolation is not so successfull with landscapes. In that case, we DO want to see new details unfold as the image is enlarged. That means the details have to BE THERE in the original image in order to be upsampled. The algorithm can't create new blades of grass or leaves in a tree.

 

To be sure, this is true with film, too, which is why so many landscape photographers have always preferred larger formats. But the ease with which digital is enlarged makes the failure more visible with digital images (what proportion of 35mm film users ever produced a 100x print and THEN inspected it at a 12-inch distance? Yet the proportion of DSLR users who do that with digital images is 100 percent).

 

The 300dpi figure for prints is based on the human eye's ability to resolve detail at normal reading distances (a third to half a meter). Although theoretically print dpi can be less than 300dpi at longer viewing distances, I find that as a practical matter people will still get as close as normal reading distances to inspect a photograph, if it's physically possible for them to do so--especially if they are photographers themselves, and especially if it's a landscape photograph. So I almost always base my print resolution on 300 dpi.

[SCL]

At that distance I think I'd stick with a safe 8x10, maybe 11x14 max. At 6 ft, you could probably get to 16x20 safely (assuming you used a tripod for the shot and were fastidious in post production).

[photojoe]

I've got a 20x24 on the wall that looks great. It's from my 7D. When I got it from the lab I was disappointed. 150 DPI, YUK! (Yes, upsampled from the 3000x2000 camera image.) When hanging on the wall under glass with a couch forcing a minimum viewing disance of 5 feet it looks stunning. The closer you are to a photo the higher resolution you need.

 

I've got a rule of thumb for myself, if you hold it in hand it needs to be 250DPI(12x10 for the 7D), if it goes in a frame that self stands it needs 200 DPI, if it goes on the wall 150 DPI is good. If you're viewing it from across the room 100 DPI will do, from across the street 3 inch tiles formed into a moasic will be acceptable... but that's me.

[clives]

I have a 7D and have made 11 by 14s and they are fine. A Canon (6MP) user and I are doing a show next month and will be doing some 16 by 20s...they will be fine.

 

Lot of truth about distance. I did a shoot for a truck poster a few years ago using slide film. Final image was 2 m tall and (I think) was at 45 dpi..remember this is on the side of a large truck box. At 5+m it is a great shot. Of course up close, the pixels were obvious.

 

Clive