What You (Probably) Don’t Know About Digital Photography… And Should


Photography: net_efekt

For many people, the differences between digital cameras and film cameras are clear: there’s no film, memory cards are reusable and you get the results right away. What more do you need to know?

In fact, it helps to know quite a bit. There are a number of facts that look small but actually have an important influence on your pictures, the way you take them and what you should do with them.

Here are some of the most important.

1. JPEG Images Lose Quality Every Time They’re Saved
JPEG (which stands for Joint Photographic Experts Group — the committee that created the format) is not just a means to store images. It’s also a way of compressing images. Each time an image is opened and saved in the JPEG format, the compression tosses out a little more information, reducing the size of the image but also lowering its quality. The more you save, the worse the image gets.

That might be fine for uploading to the Web or viewing family snaps, but when you’re shooting for money, it pays to shoot in RAW so that you have a permanent “negative” that remains high quality.

2. Sensor Size Matters
The light-recording sensor in a digital camera tends to be much smaller than the 36mm x 24mm frame standard in a 35mm camera. To record the same amount of information as a film camera then, the lens on a digital camera has to use a shorter focal length.

Photo.net has a detailed description of what that means for picture quality but the bottom line is that the smaller the sensor in your digital camera, the lower the quality of the information reproduced through the lens, especially at high f-stops.

3. Commercial Users Can Have Prohibitively High Quality Demands
Although some photography buyers will be happy to purchase images taken on the $500 digital SLRs — and even on the lower quality cameras — used by serious hobbyists, many outlets do expect much higher quality. Niche stock company GoGo Images, for example, expects its photographers to supply 50MB images shot on full frames.

That means that some commercial photography opportunities will be unavailable to all but the most dedicated — or professional — photographers.

4. Few Digital Cameras Can Compete with the Resolution of Film Cameras
According to Hewlett Packard, if you could measure the resolution of 35mm film in pixels, it would be around 20MB. Even a simple film camera then would have the quality of a top-end digital camera — and only a top-end digital camera can produce the quality of a standard film camera.

5. Many Leading Photographers Still Shoot on Film
Perhaps it’s not too surprising then that a number of top professional photographers have turned their backs on digital photography, and are still putting their images on celluloid. (We highlighted a number of them here.) Whether that’s for convenience or quality, they prefer to skip the ease of storage and delivery in favor of old fashioned darkroom work.

6. You Can Have Too Much Resolution
Higher resolutions might be necessary for some photography jobs and they always give more options, but you don’t need 20MB images for every purpose. In fact, there are times when high resolutions can work against you.

Print a high-res image on a low-res printer for example, and the printer will downgrade the image itself in order to process it. That’s bad enough but upload a high-res image to the Internet, especially on Flickr, and there’s a greater chance that someone will steal it.

Keeping your images small and low-res is one of the best ways to limit its use for picture thieves.

7. The number of Megapixels in your Camera isn’t the Number of Megapixels in your Camera
Buy a 4-megapixel camera and you’ll be told that you can shoot an image that’s 2,240 pixels wide and 1,680 pixels high without loss of quality. That sounds impressive enough but 2,240 multiplied by 1,680 is 3,763,200 pixels. Where did the other 236,800 pixels go?

The answer is that they were lost to circuitry needed to record the light hitting the sensor and it happens on every size of camera. It’s a bit like buying a new computer. No matter how large the memory on the box, you always have to round it down a bit to get your true figure.

8. Megabytes aren’t the Same as Megapixels
The difference between the stated number of megapixels in a digital camera and the actual number is confusing enough. The similarity between megabytes and migapixels is even more confusing. They’re not the same. One megapixel is one million pixels; one megabyte is 1,048,576 bytes of computer memory.

A camera may require more than one byte to store one pixel so again, you could end up with less than you thought you were paying for.

Digital cameras aren’t very confusing but when you’re investing in equipment and hoping to sell images, it’s worth knowing exactly what you’re buying.

20 comments for this post.

  1. Eric Said:

    Just a tiny clarification:

    JPEG loses information after each edit and subsequent save. Merely copying it (Or doing a "save as" or even a plain old "save" without any changes) results in an exact duplicate of the file, with just as much information as the original had.

    JPEG is a fine format if you don't plan on doing very much (or any) post processing to the image.

  2. Phil Said:

    So cross-referencing #8 to #4, shouldn't #4 say "...if you could measure the resolution of 35mm film in pixels, it would be around 20Megapixels", rather than "20MB"?

  3. Randal Ketchem Said:

    Why do you use MB when referring to resolution? They have no bearing whatsoever on each other. If using JPEG, more detail means a bigger file. Large areas of continuous tone compress better, so reduce file size, but not resolution. State the resolution in pixel dimensions.

  4. Corey Scherrer Said:

    From Randal.. "Why do you use MB when referring to resolution? They have no bearing whatsoever on each other."

    Not exactly true. They both tell you fundamentally how many bits of data the image contains therefore its size (this doesn't apply to RAW if you understand what a RAW file is).

    For example I need to generate 50-30-15 and 1mb files for our distributors. To do this easily I use a simple formula based on pixel dimension and run a batch operation in either Lightroom or Photoshop.

    I know I am working with a 300dpi file at 8 bit so I use a "long edge" pixel dimension to get the correct "uncompressed" MB size

    For example:
    the Long edge of a 50MB file is always 5150 pix
    30MB is 4011 pix
    15 MB is 2828 pix
    and 1 mb @ 72 DPI is 771 Pix

  5. kdaphoto Said:

    you left fear out of the reasons why many professional photographers has not switched to digital. Fear of change, fear of having to learn a new work flow. Its very real.

    Also, just because some top pros won't change that doesn't mean the change isn't happening. How many pro film labs are still in operation in your town? How many have switched to digital services and film is a small portion of their business. How much space does your pro photo store dedicate to film paper and chemicals?

    All very telling signs.

  6. Charles Said:

    "According to Hewlett Packard, if you could measure the resolution of 35mm film in pixels, it would be around 20MB. Even a simple film camera then would have the quality of a top-end digital camera — and only a top-end digital camera can produce the quality of a standard film camera."

    No. A simple film camera would just have the same amount of resolution as a top-end digital camera, not quality. Megapixels/MB and resolution have little to do with image quality.

  7. Fadzly Said:

    Some very useful point you have highlighted in this posting. And I've read through the comments too and most are very useful too. And I like what Charles (right before me) have just said

    "Megapixels/MB and resolution have little to do with image quality", but like it or not in an industry the measure of quality need to be quantified in some sort of unit of standard. The absolute unit of measurement can only be determined by the person assessing the image which is quite subject in my opinion. Like the old saying "beauty is in the eye of the beholder".


  8. kdaphoto Said:

    The size of pixel has a lot to do with the "quality" of the image. By that I mean reduced noise. More pixels does not translate to better image quality.

    Of course something as basic as proper exposure still has something to do with it.

  9. rprebel Said:

    I learned how to process my own film in high school, and it's actually pretty fun. Relaxing. Anyway, I am going to hold off on switching to digital until someone releases a digital SLR that's as good as my Canon Rebel XS (1st gen). Right now, the only candidates (if any) are still in the four to five figure range. The tech is still...well, it's beyond infancy, but it's also not walking yet. Until it starts walking, I'm sticking to cellulose. This article only reinforced my beliefs.

  10. steve Said:

    What the first poster "Eric" said was incorrect.

    'save as' re-does the compression again, and therefore loses quality if you aren't choosing quality 12 with progressive sampling in photoshop or something. That means, you open a file, save as something, then open that file, save as, open that file, save as.... you will lose quality every time. If, however, you edit a jpg, save-as, edit the same, and save-as over and over, the original quality never leaves no matter how many sub-files you created from that file. Only subsequent re-openings of "child files" or copies of the original will cause compounding loss.

    If, however, you use a .psd file, you can do as many edits/save-as as you want because it is a 'lossless' format saving per-pixel information for every layer. Doing a save-as from the edits on a .psd file is the ideal way of generating new .jpg files from a single photo. Don't create a new .psd, simply open the original and make .psd revisions. You can even make new layer sets for each revision of the original. Not the most space friendly, so remove any revisions not needed. ALWAYS SAVE YOUR ORIGINAL, DO NOT EDIT ON THE BOTTOM LAYER, COPY IT TO A SECOND LAYER! Keep the .jpg or RAW file your started with, these are your gold people. If the .psd gets corrupted, you can always start over from the original.

  11. KEN Said:

    There's lots of misleading information in this post (the JPEG thing especially).

    I can't believe that you are saying that lots of professionals are still using film.

    It's almost impossible to continue using film for professional shoots. It's too expensive. Processing takes too long. Clients expect the photos immediately and usually sent by email or web. And then they don't want to have to have slides or negs scanned.

    Shooting film is a recipe for going out of business.

  12. Mark Said:

    Your point #4 is incredibly misleading, and only promotes more misinformation. Much of the information in a film scan is film grain. DSLRs that cost less than $1000 USD easily produce details that exceed that of 35mm film originals.

    Your point #5 is also misleading because the same thing could be said that "Many" Professional photographers are now shooting digital, and certainly more than a handful could be shown as evidence.

    It is unfortunate that this misinformation continues to be spread on the net. You really owe your readers a retraction.

  13. Cyrus Said:

    I was astonished to read many of the points you have alluded to, since I know them to be false, per the trends I've experienced as a professional photographer with 25 years experience.

    I agree that you need to retract this post. The information is incorrect and the conclusions are misleading.

  14. Craig Ellis Said:

    I have a film SLR camera,and have taken hundreds of pictures over the years. Film pictures are only as good as the developer. A one hour lab used too develop my pictures and they came out beautiful, but wasn't cheap. When they closed down, I had them developed at...."walmart".. Colors were washed out, grainy..terrible! I lost interest in photography until I bought a Sony digital camera. My pictures are beautiful, and I don't have to wait and see what came out. I can enhance them with Picassa..My film camera is old school gathering dust...

  15. Matt Needham Said:

    Take the challenge. Shoot a subject/scene at ISO 100, 400, and 1600 with 35mm film, and then again at the same ISOs with an 8mp Canon 20D or 30D. Have someone who knows what they are doing do the film and digital processing. Order 12x18 prints, hang on the wall, and compare with your own eyes. That's what I did when I was a "death B4 digital" film geek. I used to think it required 20+mp to match 35mm film too, but my eyes saw it differently. At ISO 100 35mm has a chance, but 8mp APS-C digital still looks cleaner and sharper. At higher ISOs there is no comparison. At ISO 1600 a 20D beats 35mm Fuji NPH 400.

  16. Joseph Johnston Said:

    It's time to take this post down. You sound like you're trying to sell chariots in an age of bullet trains. It hurts your credibility and misinforms people. I almost wonder if you have some kind of vested interest in film cameras.

  17. Jonathan Jones Said:

    Horses for courses.

    When I'm working overseas, in the wild or on work that demands it (such as fine art), I will always work with film; either black and white or colour tranny. In most remote places there is a limited ability to recharge batteries and maintain an environment suitable for sensitive electronics. Plus my fine art clients seem to prefer to purchase hand crafted prints printed from film! Why? Who knows but it must have something to do with the craft aspect of the whole thing.

    Digital cameras are fantastic - they have their place for immediate delivery of commercial work. They are also convenient, fun to work with, and I don't have to carry truckloads of gear.

    Digital photography has spawned a massive new IT business ... but it has also created the myth that somehow photographers must move to digital and forego film.

    From my perspective, as a professional photographer, it's more important to focus on the quality of work produced than the medium it's produced in.

    Digital has democratised photography - anyone can take a well exposed picture. Well composed and creative ...?

  18. DancingSalome Said:

    I quite recently sold (not set aside for occasional use) my digital equipment and bought a 6.5x8.5 inch view camera. I am not frightened by digital; rather, I find halos around bright objects against midtone backgrounds, purple and red edging on bright objects against dark backgrounds, moire patterns, and purple and blue edging on dark objects against light backgrounds to be unsatisfactory for my imaging. Certainly the vast herd is willing to trade off quality for convenience, as the popularity of digital imaging attests. Oh, and by the way, despite what people anxious to sell their books and workshops tell you, a digital-negative platinum contact print does not remotely approach the quality of a film-negative one.

  19. Loraine McCall Said:

    As the saying "whatever floats your boat" I think that it is important to realize that I could look at a Picasso and say it's hideous and give my reasons for it. But really, as long as we like what we do and how we do it, there should be no question about about our personal preference. Also if in doubt, just try other equipment/techniques out and see what works for you!

  20. John Kobeck Said:

    I though this argument was put to bed a long tine ago? Its a well known fact t hat digital can't compete with film. Real photographers use film.

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