Calculating the limits for enlargments

[dougoh]

I'm taking my first shots with a new Canon Rebel XSi and really enjoying it.

One of the main reasons I upgraded from my former Fuji Finepix was the shift from 5.1 to 12.2 mp for the purposes of enlarging my prints significantly while maintaining clarity/sharpness.

I just "experimented" with my first enlargement (20x30). I am pleased overall but it isn't as sharp as I'd hoped. Am I pushing the limits of the 12.2 (the camera currently is set at the highest resolution setting: RAW+ L).

If I'm reading my display correctly the parameters were 1/13, F36, ISO 100.

Hopefully this all makes sense. Not confident in asking intelligent questions yet!

Got the poster print done at SAM's (very reasonable for my budget). Is there a big difference from a printing stand point (location, technique).

Thanks in advance for any input anyone can offer.

[Colin Southern]

I'm taking my first shots with a new Canon Rebel XSi and really enjoying it.

One of the main reasons I upgraded from my former Fuji Finepix was the shift from 5.1 to 12.2 mp for the purposes of enlarging my prints significantly while maintaining clarity/sharpness.

I just "experimented" with my first enlargement (20x30). I am pleased overall but it isn't as sharp as I'd hoped. Am I pushing the limits of the 12.2 (the camera currently is set at the highest resolution setting: RAW+ L).

If I'm reading my display correctly the parameters were 1/13, F36, ISO 100.

Hopefully this all makes sense. Not confident in asking intelligent questions yet!

Got the poster print done at SAM's (very reasonable for my budget). Is there a big difference from a printing stand point (location, technique).

Thanks in advance for any input anyone can offer.

Hi Doug,

A 30 x 20 inch or cm?

If inches then you'll have had a print density of around 100 ppi which, although not stellar, should be more than adequate.

These are the print sizes that I do almost every day and I can tell you that correct sharpening is BY FAR the most important thing. If you haven't capture sharpened and creative/content sharpened the image prior to print then it will look a bit soft up close.

On the "flip side" - apart from photographers (who's standard viewing distance is limited only by the length of their noses), nobody looks at a large print up close (and I mean nobody!).

[dougoh]

Colin,

Thanks for your response.

The poster I had printed is inches. I am learning to use the software which came with the Canon (sharpening, contrast, etc).

I'll keep tweaking and learning.

Thanks again.

Doug

[Colin Southern]

Colin,

Thanks for your response.

The poster I had printed is inches. I am learning to use the software which came with the Canon (sharpening, contrast, etc).

I'll keep tweaking and learning.

Thanks again.

Doug

Hi Doug,

No worries.

Sorry, but I've got no idea as to sharpening regimes with Canon software (probably DPP?) - the good news is though that if you ever change to Adobe Photoshop then I can help

[Geoff F]

If it is Canon DPP then the editing options are a bit on the basic side without the ability to use any of the 'clever' sharpening methods.

And if I read Doug's exif details correctly, the aperture was F36. While I don't know which lens was used, F36 does seem a bit extreme and likely to give a rather soft image compared with the middle aperture settings which are generally the sharpest.

So it is possible that the photo was a bit soft to start with and only received the DPP simple sharpening. But without seeing the original it is difficult to know exactly what to advise.

[dougoh]

Colin and/or Geoff,

I've not been able to upload any photos to my first album. How do I manually resize something so it fits the specs. I'd like to let you look at some of these "first" shots so you can get a better idea.

A message I get tells me something about a "missing security token"...

Someone connected with the website gave me some pointers but I still can't seem to upload anything.

Told you I was "green"!

dg
Thanks.

[arith]

I can't follow this; everything based on sharpness but I thought it was about size. Well, some things can be big and not sharp but look nice. The only reason I'm here though is because using RAW+L is unnecessary using up memory card space for something not needed.
Why not use RAW+S because you only want the RAW file; if you can have RAW on its own even better option.

[dougoh]

Sorry for the confusion. This was my first time enlarging a photo to that dimension and was not sure if the softness was due to going beyond what 12 mp can do (I understand know that it's not) or was it in my camera setting and/or photo editing.

I also made a mistake the first time when I said it was recorded in RAW +L. It was the highest JPEG setting of L (12M 4272X2848). The RAW settings I have are RAW and RAW+L.

Anyway, I was trying to orient my expectations in terms of printing. If a 20x30 enlargment is within the range of my camera/sensor, I will focus on fine tuning the settings and the editing to get the sharper end results.

[Colin Southern]

I can't follow this; everything based on sharpness but I thought it was about size. Well, some things can be big and not sharp but look nice. The only reason I'm here though is because using RAW+L is unnecessary using up memory card space for something not needed.
Why not use RAW+S because you only want the RAW file; if you can have RAW on its own even better option.

Or better yet, why use any kind of "+ JPG" option at all? I'd be perfectly happy if the ability to shoot JPEGs was removed altogether from my camera.

[dougoh]

Is the RAW advantage the ability to maximize editing possibilities? Is there any correlation to having a sharper end product because of the amount of info recorded?

[Colin Southern]

Sorry for the confusion. This was my first time enlarging a photo to that dimension and was not sure if the softness was due to going beyond what 12 mp can do (I understand know that it's not) or was it in my camera setting and/or photo editing.

I also made a mistake the first time when I said it was recorded in RAW +L. It was the highest JPEG setting of L (12M 4272X2848). The RAW settings I have are RAW and RAW+L.

Anyway, I was trying to orient my expectations in terms of printing. If a 20x30 enlargment is within the range of my camera/sensor, I will focus on fine tuning the settings and the editing to get the sharper end results.

Hi Doug,

Viewing distance is the key to all of this; I could shoot something with a 0.3MP camera phone and it would look sharp from a low-earth orbit if printed large enough.

Remember - as print sizes increase, so does viewing distance (for normal people anyway) - for some reason it's only for photographers where as print size increases viewing distance stays the same (ie "nose length").

In terms of how images look up close, that all comes down to sharpening and print resolution. A resolution of 50-70ppi will look rough up close - 100 ppi with look "OK" - 180 will look good/great. Anything above about 180ppi is unlikely to produce significantly superior results; I'm not ruling it out altogether, but you're really into areas where it depends on how good your eyesight is / the texture of the paper etc. Keep in mind that even 100ppi is up to SIXTEEN tone changes in every square millimeter!

For what it's worth, I try to work around 180ppi, but I'll accept down to 100ppi. If it's above 180ppi then "so be it". Printer drivers up-sample to whatever then need anyway (eg 1440 dpi for mine).

[dougoh]

Very helpful. Thanks!

[Colin Southern]

Is the RAW advantage the ability to maximize editing possibilities?

Yes.

Is there any correlation to having a sharper end product because of the amount of info recorded?

In theory, but in practice a max-quality jpeg will be indistinguishable from a RAW -> TIFF/PSD shot.

[mrsoto]

Is the RAW advantage the ability to maximize editing possibilities? Is there any correlation to having a sharper end product because of the amount of info recorded?

Hello dougoh
All photos are digital processed, if you get JPG images from your camera the edition start inside this device, but, w/out too much control.

JPG is a final format, very well compressed paying loosing information, like 32Bits MP3. if you want to enlarge then make all the work using original pixels and in 16bit space.

I do not use PS which cost more than our camera, I all ways use RawTherapee (RT) which is for free. Benchmarks suggests that produce better results than Camera Raw and Lighting

RT let you enlarge + sharp to a 16/8bit tiff file or 8bit jpg if you want to save space.

Looking at this workflow http://www.rawtherapee.com/data/RT-I...rkflow_2.4.pdf you may observe how many steeps was missing when the original JPG was enlarged

Try it and hope will love your photos

[Dave Humphries]

Hi Doug,

Just to state the obvious, not just for yourself necessarily, but anyone else reading these words; "RAW+L" just means RAW plus a Large jpg, and similarly RAW+S means RAW plus a Small jpg. The setting doesn't affect the RAW at all, it is either on or off.

Hence you are using up card space on what is effectively a duplicate image; the L or S jpg, which is a lower quality, if more instantly usable image. You can generate one of those quite quickly from the RAW on the computer.

Thus the suggestions not to bother with the "+L".

EDIT Subsequent thought: it is also possible that the size of the embedded jpg inside the RAW may be affected by the setting. Maybe I opened my mouth too soon.

Cheers,

[cienfuegos]

Several magazines use the 300DPI as their minimum criteria for sharpnes. This is not a scientific answer. We are talking about natural megapixel count, not interpolated.

I agree that viewing distance should be factored in, but forget it about a resolution of only .3 MP. You can tolerate as little as 100DPI and have a pleasant picture. Enhancements like sharpening do help, but they do not increase resolution.

Remember that the ultimate sharpness/resolution issue has to do with Modulation Transfer function. MTF. I can provide refences if you care to get that much into it. Rule-of-thumb. A 6mp camera with a well taken image (no blurring, great lens) should yiel a great 8x10" and decent 11x14".

[dougoh]

Again, helpful.

The other thing as I think back to the shot in question, I was too close to the first stone (a vertical shot of a cemetary wall) and I believe that threw off the depth of field/clarity a bit.

Modulation Transfer... makes my brain hurt! Maybe after I figure out how to take decent pictures...

Thanks again.

[Colin Southern]

Several magazines use the 300DPI as their minimum criteria for sharpnes. This is not a scientific answer. We are talking about natural megapixel count, not interpolated.

Out of interest, we've also had the same criteria from printers for high-end calenders. Sometimes we've had shots that fell below this requirement due to cropping, so we've just up-sampled them back to 300ppi ...

... and they've never noticed

I agree that viewing distance should be factored in, but forget it about a resolution of only .3 MP.

You'd be hard-pressed to find a 0.3MP camera these days - I only made the comment to illustrate the point re: viewing distance. I have seen side-by-side comparisons of (small) photos taken from an iPhone (2 or 3MP), 450D, 1Ds3, and all the way up to a 45MP Hassleblad with 45MP phase one back ... and you really can't see any difference (although obviously you do once the print size is increased).

You can tolerate as little as 100DPI and have a pleasant picture. Enhancements like sharpening do help, but they do not increase resolution.

Increasing resolution past about 180ppi quickly gets into "the law of diminishing returns" category, but correct sharpening (taking print size and viewing distance into account) has a dramatic effect, regardless of the resolution. So I'm not disagreeing with you - but in reality I find that the thing that lets most photos down isn't lack of resolution - it's lack of effective multi-pass sharpening.

[dougoh]

fyi to all who have given me the helpful input. I finally uploaded some photos to my first album. Mostly shots with my new Canon, a few with my old Fuji.

I welcome any input on anything you see. The one picture I enlarged was "cemetery wall".