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03-03-2011, 09:47 AM   #1
Designosophy's Avatar

Join Date: Sep 2010
Location: Northeast Philadelphia
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Posts: 1,098
K-7 and K-x low-light noise comparison

I've had my K-x since July of 2010, and I absolutely love it. It's my first DSLR and I am very happy with its performance, overall. In the interest of improving my photos, but without much in the way of means to purchase, I began to acquire manual focus lenses.

I found manual focus to be difficult with the K-x, particularly with shorter focal lengths. So I was considering selling the K-x and upgrading to the K-r. This would give me AF indicators, as well as interval shooting, which I also wanted. But I had also heard a lot about front focus problems with the K-r. An AF indicator would not help if it did not accurately indicate an in-focus area.

On a whim, I decided to check out the K-7, and it sounded like the perfect solution. Priced used the cost is similar to the K-r. It offers a pentaprism viewfiinder with 100% coverage, as well as AF indicators, so it should be even better than the K-r for manual focusing. And with only one stop less sensitivity than the K-x, it should meet my needs, I thought. After all, I don't use ISO 12800 all that much.

I received my K-7 yesterday and it's a great camera. It is easier to focus (though a focusing screen designed for manual focus would still help). It is, however, noisier than the K-x. Much noisier. And it also loses a lot more dynamic range at high ISO than the K-x. Everything else being equal, I would say that the K-7 is noisier at ISO 3200 than the K-x is at ISO 12800. Here are a few 100% crops.

K-7 ISO3200 1/100

K-7 ISO6400 1/125

K-x ISO6400 1/160

K-7 ISO3200 1/160

K-x ISO3200 1/320

K-x ISO12800 1/160

K-7 ISO3200 1/160

K-x ISO12800 1/160

I realize these are not scientific comparisons; however, I believe that they are informative. It's going to be more difficult than I thought it would be to decide which camera I want to sell. I have to sell one; if I could afford to keep both, then I could afford a K-5!

03-03-2011, 09:58 AM   #2
aleonx3's Avatar

Join Date: Jul 2007
Location: Brampton, Ontario
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I agree with you on the noise level of the k-7 since I have it. And I do find that it is slightly better than my K10D. OTOH, I would agree that K-x is better noise control wise in higher ISO. It is likely a good combo for you now if you intend to use one as a backup. I use my k-7 as my main camera and K10D as backup and I seldom go beyond iso800; anything above it, I would use a flash anyway. When the time comes to upgrade (either k-5 or something newer), I would phase out my k10D and demote the k-7 to backup.

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