digital cameras again

[darryl]

I have searched through the archives and on the net for info on digital cameras and found much info. What I haven't found much on is print quality from the image file. It's obvious that a higher mpxl camera will give a larger print before quality suffers, and that camera noise performance plays a part. I'm sure other factors play a role, but I don't want to go too deep in this post.

My current camera is a 4mpxl. How large of a print could I expect to get before the quality suffers? If I move up to a better camera, what important specs should be met to give some kind of optimal performance as far as printing? I would like to get really good quality in the 8x10 size.

I would like to buy a new and better camera, and have at least these needs- zoom range more than 6, operation on AA cells, large viewfinder, and the best resolution and noise performance that I can afford. I'd also like to use my SD memory cards and be able to download through my usb1 port. One other thing that will be important to me is to not have to click through the menu that much to make use of the variable settings features. I'd like to be able to arrange a few different user settings, then have them available via the rotary switch that many cameras have now.

I'm not against spending several hun but I don't want to go a grand or more, though I realize that I can get a nearly fantastic camera for that kind of dough.

I've checked through some of the camera reviews and now I'm dizzy. I know many of you are into this in a large way and could probably make a recommendation off the top of your heads. Without sending anyone off into camera review land, what would you suggest?

[Doc Nickel]

Commerical "one hour" photo printers typically print around 300DPI (dots per inch.) A 4x5" print, therefore, needs at least one million, eight hundred thousand pixels, or 1.8MP.

An 8x10" then needs 7.2mp.

However, photo image files can be easily up-rezzed a bit, with minimal, if any, degredation of the image quality. I have two DSLRs, an 8mp and an 8.2mp, and I've had images from both printed as large as 18"x 24", and they still look crisp and sharp even up close.

4mp should be able to do pretty decent 8x10's if the print shop is reasonably competent. (Or if you have a really good home printer and take a few minutes prep time with a graphics program.)

For a new camera, look at Canon's Powershot line, like the A540. They tend to get good marks, and I've heard good things from them (though I haven't used one myself.) I think they take SD, and 'bout everything has a USB port (though I don't recommend it, it's much faster to get a good card reader.)

Doc.

[darryl]

Here's another q- I've more or less taken for granted that the resolution selection equates to better picture quality the higher the resolution selected. I know that the picture size varies with this selection, but I've just now done a test to see the actual differences in the picture in the different resolutions. With no manipulation at all except reducing each image to 800x600 (or 800x594 in the case of the original size of 2304x1712), the images taken in the three highest resolutions looked exactly the same on the screen, and were almost exactly the same size in mbs, that is within 3k of each other for a 1.8 mb file size.

I excerped a selection from each large image and made these excerpts exactly the same size each, and there is no discernable difference in picture quality between any of them.

I am wearing my glasses, and have carefully scrutinized each image looking for changes in details, but have found none. Pictures taken at 1280x960 and 640x480 do show the expected differences in file size and picture quality. But from 1600x1200 up to 2304x1712 there is only a slight size change, and that's all I can discerne.

Would I see the difference on a print? And what is the point of having selections that are so close together- 2304x1712 vs 2240x1680? Does this actually relate to the print-out sizes that are common, such as 4x6, 5x7, or 8x10?

The people I talked to at the photo labs don't have any answer to these questions (they probably wanted to kick me for asking). Of course, the usual people at the camera shops don't know either. They all seem to have some sort of electronic devices shoved in their ears, and they don't seem to be good lip readers. A seagull could display a higher perceived intelligence level than some of these people- but I digress. I would actually like to make some sense out of these issues.

[darryl]

Thanks, Doc. I don't have a useable printer, and probably will be trying the drugstore photo print services to get my hard copies. I suppose I'll treat that as another experiment, and compare the results with my own (bloodshot) eyes. There are a lot of good pics from my vacation and I'm sure many will turn out fine.

I usually do some re-touching myself, mostly sharpening and color correction. I have used a de-noiseing program at times, with mixed results. It will be interesting to find out how far a photo service business will normally go towards refining an image before printing.

[Doc Nickel]

When you say you looked at the photos, I assume you meant on the computer monitor?

Two things: First, most canned photo viewer programs will show you the photo at a fairly 'standard' size, which will be somewhat reduced, most likely, over what you'd call "100%".

Second, as far as the computer is concerned, 100% is 72dpi- the standard resolution of computer monitors. Of course, CRTs can vary the "true" DPI- you can se a 15" CRT to show 1072x720 (or whatever) for example, and the image will show up smaller than if you had it set for 600x800.

So between these two, you might not necessarily be looking at the photo at "high resolution", or at "100%", so to speak.

Then, if you're reducing all your images back down to 600x800 or so, then for the most part, yes, they'll all look about the same, presuming you used the same software and the same settings.

And therefore, yes, for the most part all the photos would look about the same when printed. Again, most printers will use 300dpi and call it good.

As for the selectable smaller resolutions, that's simply an option most cameras have- you can get more smaller-resolution photos on a memory card than you can high-res, of course. That was more important back in the days when memory was fabulously expensive (I recall paying almost $60 for an 8MB Smartmedia card!) but less so today.

The various resolutions selected typically have to do with the camera software- for the lower resolutions, the software essentially ignores a select set of image data. (IE, only recording the data from every other photosite, or every third, etc. It's not that simple, but generally speaking, that's the basic idea behind it.)

I'm not sure I'm really answering your questions...

Doc.

[Your Old Dog]

If you are going to judge camera resolution, do it from paper prints and not a computer screen.

With the computer screen, aside from it's 72 dpi resolution, there is a tendency to "zoom into a solitary pixel", find it blurry and then rule it out. That's the blessing and curse of digital photography. Judge your prints by how they look hanging on the wall and not with a microscope unless your are doing scientific photography. It's not worth chasing digital ghost and it's expensive if you don't really use these high mega pixel cameras to their potential.

If your looking for a cheaper point and shoot I'd reccomend the Fuji Fine Pix F31d at about $250.00 This is the Point and Shoot camera that a lot of photographers carry with them just to have something when the big stuff is too much of a pain to carry.

If you want a pretty sexy digital SLR to build a system around I'd reccomend the Nikon D200 (as that's what I own) If I owned a Canon I'd likely reccomend a Canon to you

[darryl]

Ok, that's starting to clear up the confusion. One thing I still don't see is why the camera (my camera at least) can take pictures at the three highest resolution settings and the file size is the same, within 3k as I stated earlier. That's about a 2% increase in file size for the largest size vs the third lower size, hardly worth the memory savings. I can only assume the difference would show up on a print.

Maybe there are other reasons, such as maybe the camera throws away some of the information that is kept separately, and keeps only the picture info for the largest size- though I can't imagine that other info would be taking up that much memory. Still seems odd.

Another q I have is regarding resizing and/or cropping. It would seem to me that there would be certain degrees of change that would result in a poorer picture because of the interpolation process, and other degrees or %'s of change that would be more optimum. Is this ever a factor, or does it not matter at all if you change an image size by say 9% or 7%- do artifacts from cropping ever show up in a print? I understand that if you remove a large part of an image, then blow it up to some standard size, you will be left with a poorer image, but what about subtle variations when resizing or cropping-

[piniongear]

I would suggest you simply try out a digital SLR for a couple days of trial. I think the result would be that you suddenly stoppped thinking how expensive an SLR is and instead realized how limited you are using a point and shoot.
Just the elimination of that danged lag time on the shutter of a point and shoot is worth every penny of the cost of an SLR to me.
Use a system like Nikon and even an old manual lens from a 1960's film camera will allow you to make a very good shot, although it would have to be set manually.
There are some really fine deals out there that will get you a camera body and lens for very little cost compared to the features you will be getting.
If you are serious about obtaining better photos then get serious about getting better gear.
If you are not that serious about taking better photos then stick with the P&S cameras...........pg

[Evan]

Anytime you resize an image by a non-binary multiple/sub-multiple it causes some loss of detail. It isn't much but if done several time it adds up.

The changes in the amount of file space an image requires are a function of the number of pixels AND the format they are stored in. JPEG is the standard and it is a selectable compression format. The higher the compression the greater the loss but the smaller the file.

The quality selection on most cameras are a choice between low compression/big file/good quality and high compression/small file/reduced quality. The manuacturer can also play around with the defaults in such a way that three different resolutions all result in images the approximate sam enumber of bytes.

It's impossible to predict exactly how many bytes an image will require in advance. JPEG is an adaptive compression algorithm and the degree of compressionn achieved depends on the image content. Generally, the noisier the image and the more hard edges it contains the worse the compression ratio. When I made that time lapse video it contained a great deal of "noisy" detail. This resulted in the camera being off on the estimate of capacity by around 20%. Because of that it ran out of memory just before sunset.

The number of pixels in an image are not the only or even the best indicator of image quality. There are a new generation of low cost sensors on the market that are inexpensive and noisy. I will put my 4.3 megapixel Nikon up against these any time as it has virtually zero noise and on long exposures it does a dark field noise subtraction process on each exposure.

This sort of digital noise is a lot like film grain and has the same effect on the image, especially on enlargement. It will show up long before the pixels do. It's easiest to see in areas of nearly constant shading, neither too dark or light. A clear blue sky is a good place to look. There are also two main types of sensors, CMOS and CCD. CCD has better noise and low light performance but eats batteries. CMOS can be very noisy in the cheaper cameras although Canon uses them in their digital SLR cameras and they perform very well. It depends on the process used to make them.

Comparing images that have been resized down to 800 x 600 or similar will show no discernible differences as you have wiped out most of the spatial information required to see things like noise.

There are some very good deals out there right now but there is also a very large range in performance for what seem to be similar cameras. Two items that are especially important to me are shutter delay and battery life. My Canon Rebel has less than 1/10 second delay even with the auto focus turned on and will run for 500 to 800 shots on a charge.

Also watch for inflated or misleading claims. It's starting to resemble air compressor horsepower, especially in the claims about megapixels. A lot of the lower end cameras are being advertized with impressive sounding megapixel ratings. When you look into it that is actually an upsampled image from a lower size sensor. Since resampling cannot add information to an image, but only reduces it, these claims are bogus.

[darryl]

More good info, thanks all. I'm just now checking out the range of quality- fine, normal, economy- to see how they compare. I expect that I woudn't ever use anything but fine, since the memory isn't an issue, and I want the best I can get out of this present camera anyway.

Today is such a fine day that I should be out taking pictures.

[Doc Nickel]

Also watch for inflated or misleading claims. It's starting to resemble air compressor horsepower, especially in the claims about megapixels. A lot of the lower end cameras are being advertized with impressive sounding megapixel ratings. When you look into it that is actually an upsampled image from a lower size sensor. Since resampling cannot add information to an image, but only reduces it, these claims are bogus.

-A couple of manufacturers even went so far as to claim the three individual photosites per pixel (one red, one blue, and one green) were themselves "pixels", so they could call their 4mp camera a "12 Megapixel".

Not really a lie, per se, but definitely not the truth.

Doc.

[grannygear]

I'm a big fan of analog cameras and will never give up the use of film (as long as it's available), but I see the need of a digital camera, finally, in my life. I have a nice Canon and Contax camera now, but when I go digital I will be buying a Pentax K10. Why?

10.2 Megapixels, excellent weather-proofing, simple user interface, manual focus (if desired, which I like), SD card storage, etc. Best of all: in-the-camera shake-reduction mechanism. That means you can use literally hundreds of high-quality Pentax lenses made over the years and have the advantage of the current vibration-reduction technology.

Pictures are saved in .jpg or .raw files. A 10.2 mp sensor, with decent lens and shake reduction and .raw compression, will yield an excellent, and enlargeable, final picture. Most of the professional photographers on photo.net say that 10 megs is enough for all but the most demanding enlargements. All this for between $750 and $800. Steep? Invest in the camera body, which ought to last for a very long time (magnesium, stainless steel). Used Pentax lenses can be had cheap, and are excellent quality.

I have no connection with them, and this is strictly my humble opinion.

[Michael Moore]

Take a look at dpreview.com for some very good reviews. An EE friend of mine who is also a photo enthusiast remarked how he liked that the folks at dpreview evaluated both the optics as well as the electronic sides of the cameras. There are also user fora there, and I found those helpful to see what kind of complaints people had about their cameras. Several years ago I bought a Fuji 6900Z, and much of that decision was based on the folks in the Fuji forum at dpreview saying how they liked their cameras, instead of bitching about them.

I talked to my pal today and was told that his house was burgled a few days ago and all of his recent film camera purchases (but not his old Mamiya larger format camera) were taken. He said that he was going to replace them all with a nice digital system as he has no intention of messing with darkroom stuff ever again, and the expense and bother of film when compared to the convenience of digital is enough to justify making the switch. The high-end digitals have enough resolution that he can't complain about them for the size of prints he might make. He also mentioned that with the quality of the new photo printers he doesn't see any significant drawbacks there.

cheers,
Michael

[CCWKen]

By your statements, I really doubt you will gain anything by purchasing a high meg camera. Since you don't enlarge the pictures you take now (or you would know the quality of the 4mp enlargements), your choice will more than likely be based on "the Jones' principle". Much depends on what you intend to do with the photographs.

If you're scrap booking or posting on the web, 1mp is more than enough. Even that is a waste of storage. If you're selling the pictures, that's another matter. I've taken pictures with a 4mp camera set to 1mp, cropped pictures to a third and printed them out 8x10 and still got high quality pictures. I rarely, no never, use settings above 1mp for the kind of picture I take. If I were to shoot for posters, I'd probably use the 4mp setting but I don't. For Ebay and pictures I shoot for the web, I use a .3mp setting and they're still good pictures. Quality pictures come from optics and image processing of the camera not just the CCD capabilities so basing a decision on megapixels alone is a waste of money.

Save your money and buy an updated computer with USB 2 capabilities. You'll be able to load your pictures 40 to 100 times faster. That's something you'll need if you start shooting 8mp or larger pictures. Not many photo print shops can make use of that high of quality image anyway.

[darryl]

Ken, you're right, I haven't yet enlarged an image from the camera, so I don't know how well it would turn out. Maybe it would be just fine, even if cropped to some extent. I generally don't take pictures to send via the web, except for this forum. The present quality is much greater than needed for that, I agree.

The more I take pictures, the more I find that I want more zoom capability, plus the ability to bring a small part of an image up to full size without degrading it too much. When I expand an image from my 4 mg camera, and see the coarseness of the result on my computer screen, I can only imagine that a print would look poorly as well. Where I don't see a reduction in quality, then I don't know how well a print would turn out. I would be happier to have more 'headroom' in the image file to allow for better results when heavily cropping. I'm also finding that a significant fraction of my pictures are taken with reduced light, and where I wouldn't want to use flash. To top it off, my naked eyes aren't good enough without glasses to use the viewfinder, and thus the menu.

It's hard to say how much camera I would 'need' to deal with these issues, and thus my questions were born. One or two of the electronic viewfiners I saw today were good enough to resolve the issue of seeing the menu properly (and keeping much light out), and that would be a significant improvement for me. One or two had good zoom ranges, and that would solve a couple other issues I have. The two I looked seriously at were the canon S5 1S, and the panasonic FZ 18. The canon seemed a good choice to me, but all those tiny buttons all over the place- hmm- and the swivellng viewfinder, well there's the hard to see and use thing again from my perspective. The electronic viewfinder did it for me though. The panasonic is very similar, but with a fixed lcd screen, and also a very useable electronic viewfinder. The body of this one is comfortable and a lot cleaner looking- seems like a very nice camera. Doesn't take AA's though, and I'm not too keen on that.

From there, there's a significant jump in price, and maybe from where I'm at photographically, there wouldn't be an increase in value to me.

After enduring a frustrating time trying to get as sd card reader to work with my computer, I'm left without one. Funny thing is, one of my mp3 players works in that capacity, (shows up and works like any other drive, any kind of file can be written or read) but I have it 'hardwired' in my van so it's not workable either. Good thing I had some chocholate around to soothe my nerves

Yeah, and there I am still resisting buying a new computer. The newer SD memory cards are fast enough, I've discovered, and all I really need is a driver to enable a card reader to work. My computer still does everything else I use it for, and it seems that throwing several hundred buck that way would be the real waste of money-