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Old Jan 30, 2006, 1:29 AM   #1
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Hi all,

I do alot of reading, but I am still a complete DSLR newbie. I have a Canon S2 IS and I really like it, but I've been considering a Digital Rebel XT. Basically what I want is a camera with the picture quality of a DSLR and the point and shoot ease of a regular digital camera. Am I correct in assuming I can do this with a Digital Rebel XT with a nice all purpose lens?

My question is this - how do I tell the optical zoom level of a lens from its "milimeter rating", for example, would the included 18-55mm included lens in the Rebel XT kit be equivellent of a, say, 10X optical zoom lens? if not,does such a lens exist to give megood close up capability and around a 6-10X optical zoom giving me essentially the same shooting versitility of my S2 IS but with the picture quality of a DSLR? I want to take a large variety of different pictures in high quality without lugging around lenses is what it comes down to.

Any help/suggestions would be very much appreciated,

Thanks,

Mark
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Old Jan 30, 2006, 6:24 AM   #2
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Mark,

The 10x factor that point and shoot cameras constantly market is not a very useful figure. In fact, somewhere there is a thread indicating how useless it really is. All it represents is the ratio of the maximum focal range divided by the minimum. So, a 200-600mm lens, 100-300mm, and 50-150 are all 3x lenses but they are completely different.

Now, here's the second piece of bad news for you - a DSLR is a great device, but only as good as the image it gets. That means if you put a cheap lens on the front of it you're still going to get a substandard image. In general, the 'all purpose' lenses for an SLR tend to often fall into this cheap category. The better lenses typically will have a shorter zoom range (X factor if you prefer). That is what an SLR system is all about - the ability to change lenses so you can use the right lens for the job.

So, if you want a single lens camera - stick with the digicams. There are some fantastic ones out there. Because if you go with a DSLR and a single '10x' zoom lens - your results aren't going to be any better than the digicam but you'll have spent hundreds of $$ more.
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Old Jan 30, 2006, 6:38 AM   #3
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I think you'd find this thread useful in understanding zooms.



http://www.stevesforums.com/forums/v...amp;forum_id=9
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Old Jan 30, 2006, 6:42 AM   #4
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According to the spec. sheet of the Olympus C-7070 Wide Zoom I have been reading a 4x optical zoom is equivalent to a 27-110mm SLR lens (which equates to approx. 43-176mm in dSLR terms because of the 1.6 conversion factor due to the smaller sensor size). According to the spec. sheets on the Olympus SP-500 6MP 10x Optical Zoom the 10x optical zoom is equivalent to a 38-380mm in a 35mm film slr (which again equates to approx. 60-608mm in dslr terms). The 18-55mm EF-S kit lens (28-90mm slr) is rated at 1.0x optical zoom eqivalent. The equivalent to a 10x optical zoom, in mm terms, is 380mm (slr). You will prob. need to go to $$$ 'L' glass like the EF 35-350mm f/3.5-5.6L USM to ge that kind of range in the one lens and remember that at these kinds of magnification shake will become an issue (esp. since this is not a small lense weighing about 3lb) and a tripod will become necessay. There is a 28-200mm f/3.5-5.6 EF lens and the same lens in the USM version, and also 75-300mm f/4.5-5.6 lenses in various EF, IS, and USM combinations.


I find these values to be quite irrelevant though...


The 18-55m is a cheapie lense though and prob. won't give you the high quality you want.

Check out http://www.usa.canon.com/html/eflenses/lineup/for a more comprehensive list of Canon EF lenses.

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Old Jan 30, 2006, 9:26 PM   #5
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Thankyou very much guys, I am a complete noobie and appreciate the clarification.


How about something like the EF 28-200 Lens? If im right, it has 7.14X Zoom and the Canon website reccomends it for all purpose use such as travelling. Could this work for what I'm trying to do? If I had this lens and a macro lens? (I take alot of close ups too) Then I think I'd be covering all the bases. Let me know if I'm dead wrong please :-)


Mark

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Old Jan 31, 2006, 5:39 AM   #6
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28mm isn't really that wide on a DSLR but it's not bad. The main thing to concern yourself with a lens with that range is the quality. I'd look for reviews to see what kind of results you can expect from that lens.




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Old Jan 31, 2006, 7:53 AM   #7
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http://www.rtfract.com/d70sigma.htm Also depends on how fussy you want to be, are you going to notice a big difference, or is that just something that happens when you start looking too critically and blowing them up beyond what your printer can print? I am thinking of selling my 70-300APO for something a little more portable, and then get some ex lenses for close up and long range. Have a 15-30 ex on order.
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Old Jan 31, 2006, 8:23 AM   #8
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Measuring zoom using figures like 10x is like measuring your physical location by how far you can throw a ball, or how far your car goes on a tank of gas.

You have to AT LEAST know where you are when you start, otherwise your pissing into the wind.

ALSO, since I bought my A1 I have found that I MUCH prefer the wide angle end than telephoto. Sure, I use telephoto, but I'd give it away for more range on the wide end in a heartbeat. That camera went to 28mm in 35mm film terms, meaning a DSLR would need an 18mm lens to get the same view. I still wanted wider yet (smaller number focal length).

The more zoom a lens has, the more they usually give up in wide angle. Don't fall for marketing traps, know what your looking at. Know what your going to use that super-mega-telephoto for, too, because your getting into teritory where using that lens is a challenge due to camera shake and subject movement (birding, sports? Not general purpose there!).
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Old Jan 31, 2006, 8:40 AM   #9
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What you really want is something like the Sigma or Tamron 18-200mm zoom for the DSLR.

On a Canon camera that gives the 35mm equivalent of a 28-320mm lens.

That's an 11x zoom.

Actually the X factor is useful. In general with SLRs (and other cameras too) the bigger the X factor the lower the optical quality of the lens.

But of course the bigger the X, the less you have to change lenses.

You can also pretty much read between the lines with the X factor. Most of the digicams have a ~35mm equivalent at the wide end. So that's your starting point.

I'm not really convinced that your image quality won't be better on the SLR with the superzoom either. A SLR has a lot of advantages, low noise at higher ISO, faster focusing, better low-light focusing, etc.

Having said that the 18-200 lenses would be what you are looking for, the point to make is be careful what you wish for. The whole point of a SLR is that you can change lenses.

What's your budget? What kind of photography do you like doing? Those are the important questions.
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Old Jan 31, 2006, 8:49 AM   #10
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peripatetic wrote:
Quote:
Actually the X factor is useful. In general with SLRs (and other cameras too) the bigger the X factor the lower the optical quality of the lens.
I've got to remember that one when someone asks about the x factor. :-)
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