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Old Feb 20, 2007, 6:54 PM   #1
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I am considering buying the K100D (still LOL) and I have some questions I haven't yet been able to answer:

1) My existing camera is a Canon A520. Its aperature can be widened to f2.6. The kit lens for the K100D only opens to f3.5. Obviously the K100D has a much more sensitive sensor and I would assume even at f3.5 on it, it should be able to absorb more light than the Canon A520 at f2.6. Is this correct or not?

2) Do you think is an ok idea to start off with the kit lens and learn where I want to go from there? Or, would I be better off just buying the body and getting a lens that offers slightly more range?
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Old Feb 20, 2007, 8:13 PM   #2
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Contriver wrote:
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I am considering buying the K100D (still LOL) and I have some questions I haven't yet been able to answer:

1) My existing camera is a Canon A520. Its aperature can be widened to f2.6. The kit lens for the K100D only opens to f3.5. Obviously the K100D has a much more sensitive sensor and I would assume even at f3.5 on it, it should be able to absorb more light than the Canon A520 at f2.6. Is this correct or not? ...
Not really correct. Less light gets through because the aperature is smaller, but the sensor can do much more with the amount of light it gets. I know nothing about the K100D, but almost always there is a pretty good 50mm f/(a bit under 2.0) lens available for about $100, perhaps used. That is a usefull focal length and a fast lens. I think that should be your second lens (see below).

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... 2) Do you think is an ok idea to start off with the kit lens and learn where I want to go from there? Or, would I be better off just buying the body and getting a lens that offers slightly more range?
The kit lens with any of the dSLRs seems to be a good value. Not the best, but not bad and it comes at a good price with the camera. Unless you plan to put a good amount of money (US$400+) into a lens of about the same focal length range real soon, get the kit lens.


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Old Feb 20, 2007, 8:33 PM   #3
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Contriver wrote:
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1) My existing camera is a Canon A520. Its aperature can be widened to f2.6. The kit lens for the K100D only opens to f3.5. Obviously the K100D has a much more sensitive sensor and I would assume even at f3.5 on it, it should be able to absorb more light than the Canon A520 at f2.6. Is this correct or not?
Well, no.

The lens on your PowerShot A520 is a 5.8-23.2mm zoom, with a maximum aperature of f/2.6 at 5.8mm. That is a pretty short focal length, but it works on the A520 because the camera only has a 10mm image sensor.

The kit lens on the Pentax K100D is an 18-55mm lens with an maximum aperature of f/3.5 at 18mm. That's a longer focal length, but that's what's needed for the K100D because the camera has a 23.5mm image sensor.

The f number is the ratio of the diameter of the objective lens to its focal length, and does not vary with the size of the image sensor.

At its maximum aperature, the lens on the A520 admits more than twice as much light to its 10mm image sensor as the kit lens on the K100D admits to its 23.5mm image sensor. But because the focal length of 5.8mm is so small, it's not that tough to make a lens bright enough to do that.

Pentax makes brighter lenses than the 18-55mm f/3.5, but they cost more than its $199 list price. For instance, Pentax has a 50mm f/1.4 lens that costs $299, but it doesn't zoom.

So, longer lenses cost more, brighter lenses cost more, and longer brighter lenses cost A LOT more.

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2) Do you think is an ok idea to start off with the kit lens and learn where I want to go from there? Or, would I be better off just buying the body and getting a lens that offers slightly more range?
Actually, if you've got some experience with the A520, you should have a pretty good idea what kind of lens you should get for a dSLR. The A520 has a 5.8-23.2mm zoom, whichwould be about 23-93mm on the K100D. So the 18-55 would give you a little more wide-angle than you're used to, but a lot less telephoto. If you hadn't been using the telphoto end of the lens on your A520, then the 18-55mm should be fine.

And if not, there are lots of other lenses for the K100D.
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Old Feb 20, 2007, 11:35 PM   #4
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Thanks for the info guys!

I don't find myself zooming in on things very often with my A520. Typically, I like to shoot the local outdoors scenary including a park that has alot of waterfalls (which tends to be dark most of the time due to dense forest in those parts); I like to experiment with night photography (illuminated bridges; populated valleys with artificial light); I like to do some somewhat close up stuff; and then theres just random stuff in between.

BTW, I just realized that the K100D only goes down to an ISO of 200. Is there any reason for this?

Also, as far as lenses go, do you get the most bang for the buck with Pentax?
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Old Feb 21, 2007, 12:00 AM   #5
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BillDrew, is this an example of the 50mm lens you are talking about?

http://cgi.ebay.com/SMC-Pentax-M-50m...QQcmdZViewItem
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Old Feb 21, 2007, 12:00 AM   #6
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Contriver wrote:
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BTW, I just realized that the K100D only goes down to an ISO of 200. Is there any reason for this?

Also, as far as lenses go, do you get the most bang for the buck with Pentax?
Most non-professional DSLRs have an ISO range of either 100-1600, or 200-3200. I'm not sure why this is. The Nikons also have the 200-3200 range I believe.

It's nothing to really be concerned about. If they tacked on an ISO 100 to the K100d it really wouldn't be very useful since the images are so clean at 200 already. In my opinion, the K100d's greatest strength is probably it's performance at ISO 800. Most digicams at ISO 100 wish they could look as good as the K100d does at 800.

On your lens question, that depends on whether or not you intend to use older manual focus lenses. The Pentax can use just about any lens built for Pentax in the past 4 decades, but of course the older ones aren't very feature rich. I got myself a decent collection of lenses, including a 50mm f/1.7 A, 50mm f/1.4 screw mount, screw mount adapter, 135mm f/2.5 M, 80-200mm f/4 M, 28mm f/2.8 and a 2x macro teleconverter for about $170. I ended up with a couple old film cameras, some UV filters and a decent external flash in the process.

There are a lot of used automatic lenses available as well, but they've gone up in value a lot recently, probably due to the popularity of the K100d and the K10.

If you're more interested in fully automatic lenses, I believe Nikon offers the highest quality glass for cheap.
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Old Feb 21, 2007, 12:11 AM   #7
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When you mention Nikon, are you also including the D40? I understand that it only accepts a limited range of lenses. I do like the small size of the D40 however.
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Old Feb 21, 2007, 12:19 AM   #8
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I haven't personally looked at the lens selection for the Nikons so I can't really say. If the lenses that are available look like they'd cover your needs, and if you like the Nikon camera, then I'd say it's a good starter camera. The selection will likely expand over time, and since you'd be investing in the Nikon system, it's likely that your next camera would also be a Nikon but without the limitations.

If it were me though, and it was my first DSLR, I'd be a bit concerned that I wouldn't really know what it was I might need in the future and end up discovering that a lens I'd really want to use isn't available, and then I'd be stuck having to do without or buying another camera too soon.

I wish I could give you more specific advice, but being as I'm pretty happy with my $170 selection of manual focus lenses and a kit lens (and probably a cheap 75-300 AF lens in the future), every other lens system looks like a ripoff for my own photography.
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Old Feb 21, 2007, 6:29 AM   #9
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Pentax makes very good lenses.

That said, there are four companies that make the best lenses in the world. They are Canon, Nikon, Zeiss, and Leica.

Canon lenses are for Canon dSLRs, Nikon lenses are for Nikon and Fuji dSLRs, Zeiss lenses are for Sony dSLRs, and Leica lenses are for Panasonic and Leica dSLRs. And Canon and Nikon have the broadest selection of lenses. Because of this, there are more Canon and Nikon dSLRs out there than other brands. And because of this, third party lens manufacturers (Sigma, Tamron, etc.) make more lenses, and retailers carry more lensesfor Canon and Nikon dSLRs that for other brands.

But, as with any otherchoice you willever have tomake,if you are comfortable with the features and the limitations of the K100D, then go with it.

As to the Nikon D40, it doesn't have its own motor for focusing lenses, so it will only be able to autofocus lenses that have their own motors. That places a limit on the choice of lenses available to you, but that choice is still quite good.

When you buy a dSLR, you're buying more than just a camera. You're buying the foundation of what could become a very large system. How big a system you think you might ever need is the decision you must make.

Though it may appear otherwise, I did not intend this to be an endorsement of one particular brand over another. I think the Pentax K100D is a fine camera. I think there are a lot of fine cameras. The brand of camera I own hasn't even been mentioned in this topic.
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