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Assumer
19th of September 2008 (Fri), 08:48
Hey guys. Currently waiting for the new 5DII and 50D to hit the market. I have some questions about MPs, cropping, enlargements, etc. I have read all the discussions about too many MPs and such and realize there are many factors involved but with some cropping and enlarging to say 11x16 max, what is generally considered enough in the MP arena to get a nice low noise shot? Again I realize there are many factors and I am simplifying. For sake of argument lets assume good exposure, ISO of 400 max, and nice glass.

Bobster
19th of September 2008 (Fri), 08:56
i print 8.2mpix @ ISO1600 18x12"

recently increased an ISO400 to 30x20"

Assumer
19th of September 2008 (Fri), 09:15
sounds like I don't need 21

19th of September 2008 (Fri), 09:27
When you are talking about making prints, what really matter is the dpi (dot/inch). Most people will try to stay with 300 for a nice print resolution, although in some cases 150 is sufficient. Let's say we use 300 dpi, what that means is for 11x16 size, you will need (in term of MPs):

(11x300)x(16x300)=15.8 MP

For 150 dpi:

(11x150)x(16x150)=~4 MP

So if you want to use 300 dpi, and have a native (not software interpolated) MP, to go to 11x16, you probably need 50D. This does not mean that you can really tell the difference if for example you use 40D but stay with 150 dpi, and use software like CS3 to do the interpolation.

Hope this helps

Assumer
19th of September 2008 (Fri), 09:49
Yes it helps. Thanks

JoYork
19th of September 2008 (Fri), 10:01
It's easier to think of it in terms of PPI, or pixels per inch.

Bobster
19th of September 2008 (Fri), 10:35

rdricks
19th of September 2008 (Fri), 10:38
I regularly print 16x24 from my 30D (8MP) with great results. Any of the current cameras are going to handle 11x16 just fine.

19th of September 2008 (Fri), 10:39
And bear in mind, if you are cropping a image first, having 21 MP gives you a lot more to play with if you are enlarging it again

S.E.V.
19th of September 2008 (Fri), 10:44
sounds like I don't need 21

Majority of people Do Not need more the 12mp 21mp is a nice feature but also followed by the huge space it eats up on the cf card then on your hard drive transferring and so on. If you work for a magazine then maybe. But for the everyday photog i doubt more the 12 is needed. IMO.

Sevan

defordphoto
19th of September 2008 (Fri), 10:49
I printed a 40x50 from my 10D that turned out STELLAR!!!!!! MP don't mean too much to me anymore...5DMK2 is overkill.

defordphoto
19th of September 2008 (Fri), 10:51
Majority of people Do Not need more the 12mp 21mp is a nice feature but also followed by the huge space it eats up on the cf card then on your hard drive transferring and so on. If you work for a magazine then maybe. But for the everyday photog i doubt more the 12 is needed. IMO.

Sevan

Agreed. I send 6.5/8/10/12mp stuff to mags all the time. Never a complaint.

Assumer
19th of September 2008 (Fri), 13:21
Great info guys. Another question. With the 50D being a crop sensor, what does that do to MPs? Would it reduce the real world size?

mrklaw
19th of September 2008 (Fri), 13:53
cropping can cut your MP a lot without you realising. Just trimming a bit around the edges to tighten up your framing can cut your MP in half.

defordphoto
19th of September 2008 (Fri), 14:42
Great info guys. Another question. With the 50D being a crop sensor, what does that do to MPs? Would it reduce the real world size?

The sensor and camera are designed for it. It's really a non-issue.

Panza
19th of September 2008 (Fri), 14:52
I printed A4 210x297mm with the 3.3MP D30. No problems whatsoever..

Sfordphoto
19th of September 2008 (Fri), 15:09
Great info guys. Another question. With the 50D being a crop sensor, what does that do to MPs? Would it reduce the real world size?

as far as I know, the number of MPs from a 10MP crop will equal the number of MPs from a 10MP full frame sensor. the fact that they are from a crop sensor will not affect real world size.

usually larger formats yield better image quality and noise levels, but that's a bit complicated.

19th of September 2008 (Fri), 16:29
The only difference between a crop and FF cameras/sensors with the same MP, for example 50D and 1Ds II (both have 16 MP), is that the 1.6 crop will have a smaller pixel so that it can fit the same 16MP in a smaller area (the sensor). So 50D will have smaller pixels compared to 1Ds II. In theory, the smaller pixel will be more sensitive to noise compared to larger pixels. So, again in theory, pictures from 50D will be noisier than 1Ds II at the same ISO settings (assuming they both use the same generation sensor).

Great info guys. Another question. With the 50D being a crop sensor, what does that do to MPs? Would it reduce the real world size?

Assumer
19th of September 2008 (Fri), 17:19
The only difference between a crop and FF cameras/sensors with the same MP, for example 50D and 1Ds II (both have 16 MP), is that the 1.6 crop will have a smaller pixel so that it can fit the same 16MP in a smaller area (the sensor). So 50D will have smaller pixels compared to 1Ds II. In theory, the smaller pixel will be more sensitive to noise compared to larger pixels. So, again in theory, pictures from 50D will be noisier than 1Ds II at the same ISO settings (assuming they both use the same generation sensor).
Makes sense. Thanks for clearing that up. Gives me a little more direction in deciding on a camera.

DigitalSpecialist
19th of September 2008 (Fri), 18:23
Assumer, I have printed 3 - 40x60 prints from my 5D, and regularly print 20x30s after cropping significantly on some photos. I can tell you in the early days, 20Ds were used to make some highway billboards.

Assumer
19th of September 2008 (Fri), 18:45
Assumer, I have printed 3 - 40x60 prints from my 5D, and regularly print 20x30s after cropping significantly on some photos. I can tell you in the early days, 20Ds were used to make some highway billboards.

Thanks again for the reply. This may open me up for spending more on glass then bodies.

chauncey
19th of September 2008 (Fri), 18:54
Jim...are you saying that you would not have gotten better prints from more MP and better gear to start with to start with?

Eagle
19th of September 2008 (Fri), 19:07
what is generally considered enough in the MP arena to get a nice low noise shot? MP and noise do not go hand in hand. A 8MP P&S will have more noise than a 8MP SLR. There are a lot more factors involved other than the MP.

Majority of people Do Not need more the 12mp Majority of people do not need more than 6MP. I regularly did 8x10's with a 2MP A40 P&S.

donaldjl
19th of September 2008 (Fri), 22:07
Similarly, I've done a number of 8X10 prints taken with my 4 MP Canon G2 that have come out quite well, IMO.

bohdank
19th of September 2008 (Fri), 22:29
The difference between 11 x 17 prints from a 8 mpixel camera and a 15 mpixel camera is that all the well focussed shots will print extremely well with the latter, whereas many of the former will not.

I've printed up to 11 x 17 using a 5 mpixel camera that you could put your nose against and it was sharp and artifact free. I've also printed 8 x 10's that sucked, imo.

That's the main difference having more pixels.

I would not buy a 21 mpixel camera unless it was being used with the intention of primarily generating lage prints. For the web.....2 mpixels is sufficient.

squirl033
19th of September 2008 (Fri), 22:41
i routinely print at 12x18 with my 40D without interpolation, and the results look great.

300dpi has been bandied about, and has somehow become a de facto standard for printing in the publishing industry, but the thing most people don't realize is that 300dpi is a printer setting, and has nothing to do with the camera's resolution. that being said, if you want a corresponding pixel count, you would need a camera capable of providing 300 pixel per inch resolution at the print size you have in mind. for example, at 8x10, to get 300 ppi, you'd need a file size of 2400x3000, or about 7Mp. for a 12x18 print, you'd need 3600x5400, or about 19Mp. that assumes no interpolation.

now, to further complicate matters, let's throw in a few other tidbits. one, the human eye is not capable of resolving details finer than about 150-200 dpi at best. that means that any resolution beyond 200dpi/ppi is fundamentally superfluous. it doesn't hurt to have it, and some folks will say that a print made with higher resolution than that looks "better", but in terms of detail, it really doesn't matter.

second, viewing distance plays a part. you don't look at a 20x30 print from the same distance as you view an 8x10. a 20x20 printed at 175 dpi, viewed from a normal viewing distance, looks just fine. the "normal viewing distance" for a print is generally considered to be about twice the diagonal measurement of the print. for a 20x30, that's 72 inches, or 6 feet. stand 6 feet from a 20x30 print made at 175-200 dpi, and you simply will not be able to see any loss of resolution due to the reduced pixel count.

the point of all this is that you do not need 300dpi/ppi to make a very good enlargement. and for most purposes, if you do need to upsize your image file, there are a number of good interpolation algorithms out there that will let you "pump up" your resolution to increase the maximum print size you can make.
how often will any of this actually come into play? depends. how often do you make prints of, say, 12x18 or larger? if seldom, don't even worry about it. even if you regularly print larger images, most 8-10-12Mp image files offer sufficient resolution to make good enlagements.

bohdank
19th of September 2008 (Fri), 23:03
If you send to an Epson printer, for example, at 150, it WILL interpolate it up to it's native resolution which is 360/720 (no longer sure which of the 2 it is).

The viewing distance is a rule of thumb and I do not think it is accurate for smaller prints such as 8 x 10's which people tend to get very close to. I can clearly see minor resolution differences in an 8 x 10 at 20" distance.

squirl033
19th of September 2008 (Fri), 23:36
If you send to an Epson printer, for example, at 150, it WILL interpolate it up to it's native resolution which is 360/720 (no longer sure which of the 2 it is).

The viewing distance is a rule of thumb and I do not think it is accurate for smaller prints such as 8 x 10's which people tend to get very close to. I can clearly see minor resolution differences in an 8 x 10 at 20" distance.

of course it's a rule of thumb. but even at that, the calculated "normal" distance for an 8x10 print is about 13"... apout where you'd hold a book to read it. not many folks get closer than that to an 8x10, unless they're purposely "pixel peeping"... still, at arm's length, you clearly need more resolution than you do at 6 feet. i've made 8x10's from a 2Mp camera (VERY good lens) that were acceptable, but nothing i'd sell. but you'd be hard pressed to tell any visible difference between an 8x10 taken with a 4Mp camera and one shot with 10Mp. your eye just can't resolve details that small.

bohdank
20th of September 2008 (Sat), 00:26
You may not be able to say... oh look, that part is/is not sharper but the overall image will not look "right"... and I don't have great eyes ;-)

Ya, at a couple of feet... no one will be able to tell the difference on an 8 x 10.

hollis_f
20th of September 2008 (Sat), 13:11
now, to further complicate matters, let's throw in a few other tidbits. one, the human eye is not capable of resolving details finer than about 150-200 dpi at best. that means that any resolution beyond 200dpi/ppi is fundamentally superfluous. it doesn't hurt to have it, and some folks will say that a print made with higher resolution than that looks "better", but in terms of detail, it really doesn't matter.

second, viewing distance plays a part. you don't look at a 20x30 print from the same distance as you view an 8x10. a 20x20 printed at 175 dpi, viewed from a normal viewing distance, looks just fine. the "normal viewing distance" for a print is generally considered to be about twice the diagonal measurement of the print. for a 20x30, that's 72 inches, or 6 feet. stand 6 feet from a 20x30 print made at 175-200 dpi, and you simply will not be able to see any loss of resolution due to the reduced pixel count.

I really wish I'd done a better job of bookmarking a post I once saw on a photography forum (can't even remember which one it was). In this post somebody had used the resolving power of the human eye and recommended viewing distances, then applied some simple trigonometry, to come up with what some might think of as a somewhat radical conclusion -

No matter how large you print your images something around 5MP should be sufficient!

form
20th of September 2008 (Sat), 13:21
I've seen one of my 20D photos edited and blown up to 20x30 or so, and it looked good from a distance. Up close inspection clearly revealed the resolution limits. I estimate that 12.8 or 15 megapixels would've made significant visible differences at close distances, but 21 would've been better.

Still, at the "proper viewing distance" the 20D shot looked fine.

mrklaw
20th of September 2008 (Sat), 14:18
lets flip the question.

If 4MP is 'enough' for an 8x10, then I'm assuming all you guys with 8/10/12MP cameras resize down to 4MP before printing, and archive all your shots as 4MP to save space, as any more isn't necessary?

Of course not. More is (to a degree) always better. Gives you more options.

form
20th of September 2008 (Sat), 14:23
The term "enough" used in that context means adequate; it doesn't mean the very best possible. You knowingly misused the term.

More is better in many cases with resolution, but it's also more time consuming to process and more expensive to store because additional memory and storage are needed.

4MP might be as good as it gets for resolving power in a 4x6" print. Perhaps 16MP might be the cutoff for an 8x10".

RDKirk
20th of September 2008 (Sat), 15:52
now, to further complicate matters, let's throw in a few other tidbits. one, the human eye is not capable of resolving details finer than about 150-200 dpi at best. that means that any resolution beyond 200dpi/ppi is fundamentally superfluous. it doesn't hurt to have it, and some folks will say that a print made with higher resolution than that looks "better", but in terms of detail, it really doesn't matter.

A young eyeball in good condition can easily resolve 300 dpi at 15-20 inches, which is from where the 300 dpi standard for fine printing derives. Printing companies don't spend any more money than necessary.

second, viewing distance plays a part. you don't look at a 20x30 print from the same distance as you view an 8x10. a 20x20 printed at 175 dpi, viewed from a normal viewing distance, looks just fine. the "normal viewing distance" for a print is generally considered to be about twice the diagonal measurement of the print.

Alas, people often don't abide by the rules. If you spend some time watching people at a photo gallery, you will see that people tend to move as close to a photograph as physically possible. It's not the same phenomenon as with paintings or some other art forms, but people expect to see detail in photographs, and they expect more detail to unfold as they move closer. I once saw a guy whip out a loupe to examine a landscape photograph, but I suspect he was a photographer himself.

there are a number of good interpolation algorithms out there that will let you "pump up" your resolution to increase the maximum print size you can make.

There is no interpolation algorithm that increases resolution. No software can intuit detail where it doesn't exist in the file. Interpolation prevents visible pixellation, but does nothing for resolution.

pcunite
20th of September 2008 (Sat), 15:58
Alas, people often don't abide by the rules. If you spend some time watching people at a photo gallery, you will see that people tend to move as close to a photograph as physically possible.

Indeed and thus as long as Canon offers sRAW and higher MP does not introduce noise I am fine with the increase. The only way to better 35mm image quality is to go to MFD I suspect. Here is hoping Canon moves into that sector.