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-   -   Canon 400D or Powershot A720 for DoF (

hansel2000 Dec 27, 2007 3:45 AM

Currently I have a Canon SD750, a friend of mine has bought a EOS 400D and I´ve been really impressed by his pictures with depth of field.
I prefer the smaller Powershot A720 or A650, but how much better depth of field pictures will I get with the 400D due to its larger sensor?

TCav Dec 27, 2007 6:19 AM

hansel2000 wrote:

... how much better depth of field pictures will I get with the 400D due to its larger sensor?
A lot.

You can read explanations like that on

and try DoF calculators like that on

but I think the best way to see it is

hansel2000 Dec 28, 2007 1:13 AM

Thank you so much for the links, I learnt alot!

It looks like it will be a 400D for me.

TCav Dec 28, 2007 4:48 AM

hansel2000 wrote:

... It looks like it will be a 400D for me.

What you've learned aboutis one difference between dSLRs and P&S digicams. That is not necessarily a good reason to buy a particular dSLR. There are lots (well, maybe not 'lots') if dSLRs out there, and while the Canon 400D is an excellent example of the genre, there may be others that might suit your needs better, including dSLRs that offer even greater control over the depth of field by virtue of their having larger image sensors.

To be sure, venturing into the world of dSLRs can be intimidating, and having a friend along that you can rely on for support, is an invalueable resource.

But depending on what kinds of photography (yes, there are 'kinds' of photography, plural) you want to persue, there might be other dSLRs that are better for what you want to do.

What kinds of photography do you want to try? What would you like to take photographs of?

peripatetic Dec 28, 2007 5:51 AM

TCav is correct.

The basic point to remember is that the bigger the film or sensor size, the greater control you have over DOF.

So bigger sensors are better for this control, so from small to big (digital) you have...

1. P&S
2. 4/3 system 2.0 crop(Olympus, Panasonic, Leica)
3. Sigma SD cameras 1.75 crop.
4. Canon 1.6 crop (XT/XTI)
5. Sony sensors 1.5 crop (Nikon DX cameras, Sony A100 & A700, Pentax, Samsung, Epson RD1, etc.)
6. 1.3 crop sensors (Canon 1D series, Leica M8 )
7. 35mm FullFrame i.e. 24x36mm (Canon 5D, Canon 1Ds series, Nikon FX cameras)
8. Medium Format Digital sensors - bigger than 24x36mm - up to around 36x48mm.

As the article points out, there is no downside to having the larger sensor except for cost.

There are a couple of sweetspots in terms of price/performance if you want shallow DOF.

Wide aperture f1.4 - f2 prime lenses (new and used) are available for many of the cameras in categories 4&5. You can get something like the Sony A100 + Sigma 30mm f1.4 for around $1000.

But the real sweet spot if you can afford it is the Canon 5D, which is currently available for about half its launch price of 2 years ago. Combine with some of the very wide aperture prime lenses and the results are fantastic. (I have a Canon 5D and 50 f1.2 L lens which I love.) For example the 5D + 50mm f1.4 can be got for around $2500. And Canon also have some excellent and affordable fast primes 35mm f2, 85mm f1.8, 100mm f2. As well as the L primes which cost much more but are some of the best lenses you can buy.

And finally of course you could decide to go all the way to large format film - in which case you can get yourself a 5x4 view camera plus a decent lens, tripod and scanner for a price not far from the Canon 5D + a couple of L prime lenses.

I strongly recommend reading the equivalence article above a number of times; you will find it very difficult to absorb at a single sitting. I find the section on "equivalent lenses" to be particularly interesting. The equivalence of the 85 f1.2 L on a 40D and the 135 f2 L on the 5D for example is not something you would necessarily expect from an "intuitive" understanding of the crop factor.

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