All in one zoom vs SLR zoom....?

[MARINERMAGNUM]

i guess this is a stupid question [most of mine are] but i have been using an all in one digital since i started the whole camera addiction thing. my camera has 12x optical zoom. is there a formula to convert the optical zoom into the "mm" zoom that slr's use.

like,say, what is the zoom in mm's you need to equal a 10x zoom in an all in one? is there a way to calculate it? like:

12x zoom = "?" mm's

8x ="?" mm's

etc.

i almost have my wife convinced that buying new couch with 2 small girls [who will surely spill grape juice on it the day it arrives] is a bad idea,and the money would be better spent on a new 100-400,IS-L

[Steve Foss]

A 4x zoom is about the equivalent of a 110mm SLR lens. So a 12x zoom would be a bit over 300mm. While a 400mm has a 12x zoom "beaten," in the first place, an L series 400mm from Canon is going to produce better quality images than an all-in-one zoom lens. Also, some all-in-ones automatically drop to a lower resolution setting when the max zoom is selected, which makes it impossible to make larger prints. But it's not necessarily about magnification. It's about glass quality.

And it's FAR easier to hold the 100-400L IS steady and get a sharp image than it is to try to hold an all-in-one steady enough at 12x for a good image.

DSLR sensors are bigger than all-in-one sensors. So the 20D sensor you just bought, at a bit over 8 Mp, is going to produce images with a lot less digital noise than what you get from an 8 Mp all-in-one sensor. Because the all-in-one sensor is smaller, manufacturers have to cram the 8 Mp into a smaller space than on a DSLR sensor, which increases the heat during processing, which leads to digital noise. Noise increases at higher iso settings. In an all-in-one at iso400, for example, there may be as much noise as the 20D at iso800.

[MARINERMAGNUM]

i checked out the canooga HSOforum. if she limits me to roughly $500,i have a tough choice between the 70-300 with IS or the 70-200L which one would you choose? this is grasshopper's question to the mighty master of megapixels.

[Steve Foss]

Grasshopper, to you I'm a master. To Jim Brandenburg I'm a grasshopper.

For $500 you must be talking the 70-200L f4, right? By all means, get that over the other zoom. The three 70-200L zooms are Canon's sharpest zooms (all zooms are inherently slightly less sharp than primes when shot wide open at max focal length). They are the 70-200 f4L, the 70-200 f2.8L and 70-200 f2.8L image stabilizer.

You see, if you get the 70-200L f4 for about $500, you'll have a very sharp zoom. Then you buy the Canon 1.4 teleconverter for $275 a bit down the road, and you're shooting at about the equivalent of 300mm at f5.6, which is the same specs as the 70-300 zoom you already mentioned. The 70-200 with the TC will give you better image quality than the 70-300 non L series.

Also, the 20D won't autofocus a lens/TC combo with an aperture narrower than f5.6, so you've still got autofocus capability.

I had the 1.4 TC with my 100-400L IS, but putting them together produced a max aperture of f8 at 400mm, so the 20D wouldn't autofocus it. There is a way to tape off a couple contacts on the lens or camera to spoof it and allow autofocus, but it is much slower that way, so I sold the TC (too bad for you, or I'd make you a deal on it).

But, dude, get her to let you spring for more. You can get the 400mm f5.6 L for just over $1,000 after rebate. It's the same aperture as the 100-400L IS, but it's a little sharper because it's a prime, not a zoom. No IS, though, so a good tripod is a must.

In fact, even if you go with the 70-200 and, eventually, the TC, get a good tripod. No matter how good the technique, there come times (more often than we like to think) that in order to eliminate hand shake and get sharp images we must use tripods. Get one and get used to it.