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01-17-2010, 08:30 PM   #1
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Image quality question and be nice

So, I have a question and please be nice.
I like to read and do research on different photography hardware and software.
And I was wondering how does image quality differ between Pentax K-x and Nikon D90? I know that those two are different class, and that they have different features, but I’m taking about image quality, low ISO, high ISO. How are they different?

Thank you for your time.

01-17-2010, 10:15 PM   #2
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Imaging Resource "Comparometer" ™ Digital Camera Image Comparison Page
01-18-2010, 02:09 AM   #3
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short answer....in the hands of someone who knows at least the basics and up regarding how to compose, expose and take the right photograph, the difference will be minimal. To a measurbator and those who think the real magic of photography lies in the fractions of unscientific testing, the differences may seem a little more important...then again, I am not sure if they actually know what composing an interesting photograph is all about anyway.

Jason
01-18-2010, 03:46 AM   #4
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Consider this. You walk down your favorite street/forest/museum/etc and see the scene that you'd like to capture. You bring your camera to your eye and do whatever you think has to be done: focusing, exposure, actually composing the image. You click the button. Light goes all the way through all the glass pieces of your lens and strikes the sensor. The file is written on to the memory card. Later on you download it to your computer and spend your time tweaking, processing, editing, modifying the photograph until you're satisfied with what you see.

It seems to me that camera although important is not the most significant part of this process. It is just one of many components, so to say.

I humbly suggest that you consider what I wrote and think about it a little.

Given that both K-7 and D90 are modern DSLR of medium to high class, I suppose that they both will give you great many wonderful photographs. But you'll have to solve the above equation on your own the way you like it. Noone can really do it, but yourself.

I am sorry if you expected a technical answer, 'cause it is extremely difficult or almost impossible to provide one that would be objectice and unbiased.


Last edited by Boris; 01-18-2010 at 06:05 AM.
01-18-2010, 05:24 AM   #5
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I would say that the differences are minimal. A lot more would depend on the lenses you are using. I feel like Nikon and Pentax colors are pretty similar, although in general Pentax tends to be a little warmer. The kx may be a little better at high iso from what I have seen, but understand that these differences are small and not likely to be seen if the photos were ever printed.
01-18-2010, 07:09 AM   #6
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The Kx has the advantage because of its incredibly good high ISO and in-body stabilization.
01-18-2010, 07:13 AM   #7
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QuoteOriginally posted by Boris Quote
Consider this. You walk down your favorite street/forest/museum/etc and see the scene that you'd like to capture. You bring your camera to your eye and do whatever you think has to be done: focusing, exposure, actually composing the image. You click the button. Light goes all the way through all the glass pieces of your lens and strikes the sensor. The file is written on to the memory card. Later on you download it to your computer and spend your time tweaking, processing, editing, modifying the photograph until you're satisfied with what you see.

It seems to me that camera although important is not the most significant part of this process. It is just one of many components, so to say.
.....
Boris outlined some of the important factors in the chain of making an image for display; but did not explore the logical relationship between them.

The strength of a chain is equal to the strength of its weakest link. The photographic process is logically a sequential series that can fail at any point, like links in a chain.

Not much of a camera is required for out-of-the-camera photos of adequately lit scenes shrunken in size for the web; but huge prints of photos taken at dusk or dawn are a different matter indeed.

Compare the images at comparometer carefully for the cameras in question - at high ISO if you'll ever want to take photos in dim light, like a high school gym or enlarge photos of far away birds. To me they look comparable but the K-X has a resolution edge I think.

However I'd choose the K-x on other grounds: built-in image stabilization, access to legacy lenses (not to mention lenses I already own.) Lenses are certainly critical links in the chain. A great camera with no lens is a paperweight.

Post processing with advanced software can effectively improve effective camera and lens quality a little, but is expensive in terms of your time.

Special needs might sway your decision; might you want to take photos in heavy weather? Then a weather-sealed camera might be more suitable than fighting with plastic bags.

I know that it isn't possible to know the future and what photos you'll want to take, but think about it a bit and consider investment in each link of the chain so you don't accidentally close some door.

Dave in Iowa

01-18-2010, 07:48 AM   #8
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Thank you everyone for your input. Camera will be used for personal use, not professional. But, since I have a child, I will be taking a lot of pictures indoors with low light. I also plan on taking the camera to Europe for vacations and I always attend indoor auto shows and motorcycle shows. The reason why I’m asking about the HIGH ISO, is because 70% of the pictures will be taken indoors on my little girl and I want to make sure that they don’t come out blurry. I don’t have studio lights, so I have to use room lighting, windows and flash. But, I would prefer not to use a flesh, because the little girl is just an infant. This is why I was asking which camera is better D90 and Pentax K-x in low light. I know that K-7 is not so good in low light, that is why I’m not including it.

Also, 99.9% of the pictures will be taken hand held. Again, I’m not a pro, just someone who loves to take pictures of vacations, my family, etc, who is looking to invest time and money into the right system. Boris gave me his input, but I will be honest with you, I have no idea what he is trying to say and he is taking about K-7 which I was asking about D90 and K-x.

Thank you everyone for all your inputs.
01-18-2010, 08:22 AM   #9
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Follow the link to the comparometer and compare the jpeg outputs of the two cameras.

I think the K-x would be a superb choice for your purposes, especially coupled with a fast 50mm prime lens.

Do you already have any lenses? There are a lot of reasonably priced old nikon & pentax lenses out there, but since the Pentax has built-in Image Stabilization I'd prefer it, especially as you are interested in interior shots.

I think that not all old nikon lenses work with the D90; you might check on this if you are interested in legacy lenses.

The best deal I know of is at amazon.com - $645 for a K-X, 18-55mm zoom & 55-300mm zoom. A superb set indeed.
01-18-2010, 08:54 AM   #10
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QuoteOriginally posted by pakuchn Quote
The reason why I’m asking about the HIGH ISO, is because 70% of the pictures will be taken indoors on my little girl and I want to make sure that they don’t come out blurry. I don’t have studio lights, so I have to use room lighting, windows and flash. But, I would prefer not to use a flesh, because the little girl is just an infant. This is why I was asking which camera is better D90 and Pentax K-x in low light. I know that K-7 is not so good in low light, that is why I’m not including it.
In this case, the difference depends entirely on whether you prefer to shoot RAW or JPEG. The D90 and K-x share essentially the same sensor, and in RAW their results are almost entirely identical (the K-x may be slightly sharper at low ISO due to a weaker AA filter but that will be invisible due to noise at higher ISOs. The K-x also has what I like to call a "magic" ISO 100 but that's really irrelevant to most users, particularly in your case). In JPEG the story is very different, since the K-x's jpeg engine delivers the goods at high ISO like no other camera under about $2000. The D90 is not bad by any means, but the K-x really delivers.

Also of interest for once she gets on her feet and starts zooming around (which will no doubt seem like a remarkably quick transition) the K-x's continuous shooting at 4.7 fps is actually faster than the D90's (4.5 fps), which was a real shocker to me when I noticed that just now. However, the D90's autofocus is marginally faster (you won't notice in halfway decent light) and a bit better at tracking a moving target. Really though, it's better to learn how to work most effectively with the camera's AF system than to just get the camera with the "better" AF system and expect it to take care of everything.
01-18-2010, 09:23 AM   #11
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I don't have any lenses, I'm starting new. I have $1600 to get new equipment, and if I have to go over a little it's not a problem.






QuoteOriginally posted by newarts Quote
Follow the link to the comparometer and compare the jpeg outputs of the two cameras.

I think the K-x would be a superb choice for your purposes, especially coupled with a fast 50mm prime lens.

Do you already have any lenses? There are a lot of reasonably priced old nikon & pentax lenses out there, but since the Pentax has built-in Image Stabilization I'd prefer it, especially as you are interested in interior shots.

I think that not all old nikon lenses work with the D90; you might check on this if you are interested in legacy lenses.

The best deal I know of is at amazon.com - $645 for a K-X, 18-55mm zoom & 55-300mm zoom. A superb set indeed.
01-18-2010, 12:24 PM   #12
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If you've got 1600 to work with, a K-x body is absolutely the way to maximize your dollar. That leaves you about $1000 to spend on glass, which is what you'll find is the REALLY important side of things... :-D
01-18-2010, 01:37 PM   #13
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QuoteOriginally posted by pakuchn Quote
I know that K-7 is not so good in low light, that is why I’m not including it.

If you shoot RAW, the K-7 can hold it's own against the best (Nikon D300) if you use some noise processing software. The problem with the K-7 is that the PRIME II image processor doesn't do a good job when it comes to noise. Using some software like NOISEWARE can do miracles with the K-7 files.
01-18-2010, 02:22 PM   #14
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Er1kksen,

Which lense would you get? I want something for indoor such as dinners, kids running around, indoor auto shows, etc.
01-18-2010, 02:23 PM   #15
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QuoteOriginally posted by newarts Quote
The best deal I know of is at amazon.com - $645 for a K-X, 18-55mm zoom & 55-300mm zoom. A superb set indeed.
Add to that a FA43/1.9, or a DA40/2.8 and a DA70/2.4, and you would have a fantastic kit to take great portraits of kids indoors and out, and still be under budget.
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