Digital Camera Basics

[Kurt]

I was messing around with a digital camera and noticed it had settings for shutter speed, aperature, etc like a film camera (even made a shutter click). But messing around I could not get any depth of field adjustment with the above. Then I thought to myself, "How could I since as far as I know a digital camera records light directly on photo-sensitive diodes that can be biased to react differently to light?"
Ok, then so whats the deal and can a digital camera be used to do all the things a film camera can? And how?

Kurt

[A.B.]

The lens not the camera is responsible for the DOF (Depth of Field). The shutter speed and aperture controls the lens opening and exposure duration. These are the only factors that effect DOF of the final image.

The lenses in digital camera behave the same way as lenses in film cameras. More often than not camera manufacturers use their existing film camera lenses in their digital cameras.

Once the lens (shutter speed and lens aperture) forms the image, it’s going to be recorded exactly the same whether it’s on a CCD or on film.

If the DOF of the image does not change with your digital camera then there’s something wrong with it. Are you sure you’re turning of the auto exposure and setting it manually?

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A.B.
www.ShortWheelbase.com

[Photog Rob]

A. B. is right - if you don't see a difference, something is wrong. Bear in mind that many Dcams offer only limited aperture selection and slow glass, so if you are not doing close-focus stuff you might not see the DOF increase. To make sure, zoom out as long as possible (if it's a zoom lens) and shoot very close to the subject. That way DOF differences are maximized and you definitely should see them.

A good Dcam can indeed do MOST of what a film camera can, and a handful of things traditional ones can't, like small video clips or voice annotation. They suck on long exposures though.

Notice I said a "good" Dcam. Cheaper Dcams offer worse quality than disposable film cameras. The good (and expensive) rigs are doing double spreads in your favorite magazines with no quality loss.

Roberto.

[Kurt]

Thanks for the info. I belive the camera in question was a 'good' one. Zoom lens and a manual as think as a romance novel and almost as useful. The major think lacking on the lens (keep in mind my fave camera is a manual focus Nicon SLR) was any way to guage DOF. This tiny little lens pops out like Pinoccio's nose! Are there digital cameras (near the price of film cameras) that can match up? And in the field, how durable are they? My manual SLR has bumped all over the place for years without a glitch.

Kurt

[Photog Rob]

Short answer is... no.
In the current state of technology, you can get a Dcam that's the same price as a film cam (from US$50 to 50,000), OR, you can get one as tough as its film equivalent, but not both. I give that about four to five years to arrive.

Case in point: I am currently using Nikon's D1x, their top of the line digital SLR. Modeled after the F5, it's a thoroughly pro-caliber machine, tough as nails. Sadly, over here (Spain), it sells for about US$6500, which is exactly twice as much as the F5 . Other than that, I'd take it with me anywhere (actually I do!), but I understand only a pro would pay that much for digital, unless you do golf with Bill Gates.

Also check: "digital camera" in this forum. Starting to get dated, but good info there.

Roberto.

[dagjen]

The main difference between a "standard" digital camera and a traditional SLR in regards to DOF, is the diameter of the lens. With the small diameter on most digicams, the DOF will be much higher than on your SLR. This makes it harder to take for instance close-ups of people and get a blurred background. But it also can give you some fantastic shots where you want high DOF.



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Dag
http://RocinantesTravels.com

[Kurt]

$6500 for a camera? That's more than most of the motorcycles I've ever owned. And a long way from my price range: Buy and process a lot of film with that money!

Kurt

[Photog Rob]

$6500 for a camera? That's more than most of the motorcycles I've ever owned.

Actually, Kurt, that's more than any motorcycle I have owned, being a firm believer in the second-hand market myself. I was trying to put things in perspective regarding how much more a Dcam costs in relation to its film equivalent, not suggesting anyone should get one. I need to spend those amounts, but believe me if I tell you I do not enjoy doing so.

Then again, in my case it is money well spent - it pays for itself far faster than any of my traditional cameras!

Enjoy the ride, and keep the black parts of your bike pointing down!

Roberto.