-hh said:
True, you can do this without much "problem", for its only a couple of keystrokes in Adobe Photoshop to tell it to do such an IMO bad idea.
The only real question is if the photographer is going to be happy with the results of such an enlargement (as Mike was here). This ultimately depends on the personal preferences of the person viewing the image.
The Physics based approach easily finds that a scaler enlargement to 24" x 36" from a 4MP sensor means that each pixel gets enlarged to roughly 1/64th of an inch in size. This is a bit less worse than 70dpi, which means that the image is roughly equivalent to the "coarse" grade newspaper photo, athough you've helped it out by better paper stock...its probably going to be roughly equal to a glossy paper advertising section.
OTOH, if you want "movie poster" quality, you need to roughly double your dpi's up into the "good quality offset lithography" level of print qualty, which is a data density of 133-155 lpi. Do the math to see the implications for how many MP this actually requires (hint: 2x linear x 2 dimensions equals ...).
This really is a subject area that is very open to personal preference. Personally, I don't generally merely want my prints to "look nice" from the far side of a room, but I want them to stand up to scrutiny from ~2ft away too.
For example, I have an 8x10 print hanging up that I took when my wife & I first got married. It was taken with ISO 400 film and the "obvious" grain in it absolutely drives me up the wall, and I would take it down in an instant and *burn it* if not for the fact that my wife adores the photo, looks right past its shortcomings and will not allow me to take it down...different strokes for different folks.
Overall, there's a reason why this camera is being heavily discounted.
And since very good PhD-style 4MP cameras exist for $200, I'd have to disagree that its effectively worth an extra ~$1800 for the SLR form factor. Granted, I do agree that some features are worth something...simply not that it represents "$1800 worth" of value-added.
If you normalize the price, its a bit easier of a decision:
a) Nikon D2h + 18-70mm lens is $1900 (from above)
b) Canon 20D + "kit lens" = $1350
or you can upgrade the Canon lens a bit...
c) Canon 20D + EF 28-135mm IS lens is $1300 + $400 = $1700
d) Canon 20D + EF-S 17-85mm IS lens is $1300 + $700 = $2000
Considering just these, they're either cheaper or comparable to the Nikon, and since the 20D has twice as many pixels, may be the edge even when the price is the identical.
Granted, there's still other feature elements to sort out to decide what they're worth, but each brand has its particular strengths and weaknesses. However, for the most part, these difference will matter only to the more generally advanced photographers who have already sorted out what sub-specializations within photography they're interested in, which doesn't apply here to the OP.
Similarly, even though the lens we're suggesting is a "better quality" lens, if we really had any alledgedly specialized needs, we also wouldn't be picking a general purpose lens for either brand...QED!
-hh
PS: when you don't use Ebay for prices on the Nikon, the D2h goes for roughly $2000 and the lens for another $300. Caveat Emptor.
A couple of things to mention, that you fail to. Your "PhD 4mp camera" which i'm assuming you mean a P&S cam, has an infinitely smaller sensor. IMHO, a professional SLR sensor, which the 20d (or the d70 for that matter) is not, has a better quality picture. The photosites react differently in a pro camera. I don't know all the science, but i can see a HUGE difference in the photos from my D2h when compared to my D100 or my 10d samples.
To compare this camera to the 20d is a bit preposterous, on price alone, because it's not REALLY a pro camera-- it's a comsumer camera with LOTS of pro features. The d2h more solidy would compare to the 1d or 1d mkII, the latter is only availble new for ~$4500 and the former used ~2200.
The OP wanted a camera that they won't outgrow, hence trepidation with buying a powershot or coolpix, and with good reason. The FOTM is that the Nikon offers a pro body, with pro build and a LOT of features that would give this person a lot of room to grow. And with a price of $2000, it'll hold it's value should the buyer decide in a year that 4mp isn't enough and they want to buy a D2x (or a 1d mk II even).
If the poster plans to shoot their kids sports games, a D2h trounces the 20d/d70 line of cameras, simply because it's AF is world class--fast and accurate, and the BIG viewfinder is an added plus, along with being able to do 8fps. If they're looking to do family photos at holidays, etc, iTTL is reason alone to look at the Nikon series, as iTTL is a fantastic system, on both the D2h and D70. Nikon's pro metering is fantastic too, offering spot metering (something the 20d doesn't do as far as I know. I know the 10d didn't and the DRebel mk I didn't do it, only the pro canon's) which would be helpful if you're shooting available light in say, a concert hall for a child's recital. It also has an excellent and accurate matrix meter and the classic center weighted metering, the matrix plays WAY nice with iTTL. FYI, the D70 shares MANY metering characteristics with the D2h.
Sure, all of these are theoreticals, but if the poster wants a camera to grow with, the D2h wouldn't be a poor choice at all. And I doubt they will enlarge to huge sizes, but as i've said, without interpolation software, i've done enlargements to double truck size for some various magazines i'm published in and the results are stellar.
I'd say if you go this route (DSLR ANYTHING), definitely spend time learning photoshop, it's essential, canon or nikon.
So based on MP alone the 20d kicks the D2h's arse on paper. BUT, in reality, the feature set, the 2.5 LCD (though a little inaccurate), the metering and iTTL make it really a good competitor to the 20d. You can't go wrong with either, but I think that the D2h deserves some consideration-- and many won't, simply because they go into Ritz and see Rebels, D100s, D70s, and 20d's. They don't get to see the "pro" offerings.
So many won't take into account the D2h which is priced in the "pro-sumer" range, and is a serious candidate.
That said, I don't think Canon has any right selling a $199 body with a $80 lens for a grand, 8mp or not. I don't think Nikon has any right selling a $250 body with a $200 lens for $1299, rebates notwithstanding.
Hopefully, Nikon comes out with a D50 (rumored) which would be a 6mp d70 style cam that would start, with a 28-80 equivalent DX lens for $599. Now THAT'S where we need to go re: pricing of DSLRs, which is could be a whole other thread.
Lastly, given the quality of pro sensors with the D2h/1d/D2x/1ds series, it'd be better for the poster to get an accurate 4mp, sharp, colorful, and in focus than get 8mp with a slower af causing you to miss keepers, which might not be as sharp or suffer from back focusing (which seems to be a common problem with the consumer level DSLRs). I know too many canon owners who have to send their lenses in for adjustment. Same with D70 owners.
I'd give a serious look to the D2h, you'll never want to touch a "consumer" level camera again. I love my D100 but sometimes I don't even want to pick it up-- it's a bit of a downer after using the D2h. And I think the D100 has the most robust feel of the prosumer cams i've used (10d, Rebel mk I, D30, Fuji S2, D70) and i'm sure it's on par with the 20d and i'm sure it crushes the rebels. (which it's universally agreed that the build quality is less than, um, robust, by many pros and prosumers alike).
