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03-20-2011, 11:28 AM   #1
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why my K-r consistantly sets lower shutter speed than canon Rebel T2i?

I just recently bought a K-r and a DA70mm to take my child's pictures. Yesterday, I was visiting a friend's house and he has a T2i. It was a gorgeous day so we did some outdoor shots of the kids playing in the yard. Then we noticed that when we both had the camera in Aperture Priority mode with F8.0 and ISO 10 to shoot at the same object, the K-r constantly set a higher shutter speed. For example, when shooting at a house, the Kr set it to be 1/125, and the canon set it to be 1/250; when shooting at a bike, the Kr had 1/100, and the canon had 1/200. Anyone had similar experience?

03-20-2011, 11:37 AM   #2
huh
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Attached are the comparison pictures.

Also, do you think the blur around the street number in the "house_kr_cr_cr.jpg" is normal?
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03-20-2011, 11:44 AM   #3
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Firstly, it's a little confusing when you say "higher" shutter speed. That would suggest the shutter is moving faster, and in that case it would not be the K-r with 1/125 and 1/100 respectively that would be "higher". It's much easier to understand if you just say slower and faster.

That being said, it could be a couple of things causing the Canon to choose a faster shutter speed on aperture priority. I wonder if the base ISO's being different on each camera would make a difference? ISO 100 on the K-r is the extended range from the base of 200. One would think that would make it less sensitive to light on the 100 setting accordingly than the Canon's 100 since it is not extended?

The other explanation could be minimum aperture for each lens.....you didn't say what lens was used on the T2i. The focal length could also play a factor.

The blur could be a lot of things too. From shutter movement.....to whether SR being implemented.....to the individual user and shaking.....to the particular shaking on that particular shot. It's tough to compare handheld shots.

Last edited by ccd333; 03-20-2011 at 03:26 PM.
03-20-2011, 12:42 PM   #4
huh
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QuoteOriginally posted by ccd333 Quote
Firstly, it's a little confusing when you say "higher" shutter speed. That would suggest the shutter is moving faster, and in that case it would not be the K-r with 1/125 and 1/100 respectively that would be "higher". It's much easier to understand if you just say slower and faster.

That being said, it could be a couple of things causing the Canon to choose a faster shutter speed on aperture priority. I wonder if the base ISO's being different on each camera would make a difference? ISO 100 on the K-r is the extended range from the base of 200. One would think that would make it less sensitive to light on the 100 setting accordingly than the Canon's 100 since it is not extended?

The other explanation could be minimum aperture for each lens.....you didn't say what lens was used on the T2i. The focal length could also play a factor.

The blur could be a lot of things too. From shutter movement.....to whether IS being implemented.....to the individual user and shaking.....to the particular shaking on that particular shot. It's tough to compare handheld shots.
Thanks for the reply. The lens on the T2i was Canon EF-S 18-135mm f/3.5-5.6 IS. The focal length was set to 69mm.


I checked the resolution test for both lenses on photozone.de. The DA70mm's center MTF50 at F8.0 is 2107, compared to 2436 of the other lens. Do you think the blur is caused by my shaky hands or just normal resolution for DA70 at the distance?

03-20-2011, 12:54 PM   #5
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QuoteOriginally posted by huh Quote
Thanks for the reply. The lens on the T2i was Canon EF-S 18-135mm f/3.5-5.6 IS. The focal length was set to 69mm.


I checked the resolution test for both lenses on photozone.de. The DA70mm's center MTF50 at F8.0 is 2107, compared to 2436 of the other lens. Do you think the blur is caused by my shaky hands or just normal resolution for DA70 at the distance?
I wouldn't think it be the DA70.....it's considered to have consistent resolution regardless of aperture setting.

The interesting thing to me is the Canon had the IS lens.....but are you certain you had your in-body SR on with your K-r? If not, then yes...it is more likely to be your shaky hands. If so, it might still be your shaky hands.

The other factor to consider is the extra megapixels on the T2i for a crop situation (over 50% higher resolution potential resolution.....so almost apples to oranges for cropping) If you look at the other items beside the numbers (the door for example) the blur is less pronounced on the K-r. Is there a way you can post the two door/address shots at full size with full EXIF?

The bikes don't show a big sharpness/blur difference as much as a contrast/color one. JPEG processing (or could one be RAW?) and various settings on the camera (all default?) could make a difference there. Like the default vs. natural for example......or contrast settings.

Last edited by ccd333; 03-20-2011 at 03:25 PM.
03-20-2011, 01:14 PM   #6
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Something else I just thought of.....the "faster" shutter speed difference on the Canon could also make the shot less prone to blur with handheld to some extent. You wouldn't think a whole lot, but it all adds up.

Last edited by ccd333; 03-20-2011 at 01:21 PM.
03-20-2011, 01:26 PM   #7
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MTF scores are NOT comparable across system or even different camera's as stated in Photozones reviews.. on EACH review it states this... As for the blur, it could be linked to CA's since it is black on white. Best bet would be to shoot in full manual mode anyways and set your shutter speed and ISO and then work your aperture and see what you get for blur on the house numbers. Actually looking again at your top pic of the houses, it looks like your focus is out in gfeneral... the rockwork and railing and everything is a bit fuzzy. were you using AF or maual focus? But you can definitely see the better color rendering of the K-r over the T2i, the Canon looks like it was sprayed with a matte finish, compared to the K-r's nice semi-gloss
03-20-2011, 02:41 PM   #8
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In those house shots look at the detail difference in the bricks; to me it looks like a different focus point in the photos which is why the number is less sharp in one but with more brick detail, and the other way round in the other.

Your DA70 is a far far better lens (@ 70mm obviously) than that other lens, MTF is NOT comparable cross systems.

I don't know why you are worried about different shutter speeds, what does it matter? There are many different possible reasons but none of them indicate there is anything wrong whatsoever with your K-r. I'd worry much more about what you are choosing f/8 when shooting with you DA70.

03-20-2011, 05:05 PM   #9
huh
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QuoteOriginally posted by twitch Quote
In those house shots look at the detail difference in the bricks; to me it looks like a different focus point in the photos which is why the number is less sharp in one but with more brick detail, and the other way round in the other.

Your DA70 is a far far better lens (@ 70mm obviously) than that other lens, MTF is NOT comparable cross systems.

I don't know why you are worried about different shutter speeds, what does it matter? There are many different possible reasons but none of them indicate there is anything wrong whatsoever with your K-r. I'd worry much more about what you are choosing f/8 when shooting with you DA70.
f/8 was set by my friend simply for testing. I am worried about the shutter speed because the pictures with this Kr tend to over expose a little. I did about 20 such "house number" shots on this camera today (very sunny here in northern VA). The sharpness is far better when the outside is not very bright.
03-20-2011, 05:08 PM   #10
huh
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QuoteOriginally posted by Chex Quote
MTF scores are NOT comparable across system or even different camera's as stated in Photozones reviews.. on EACH review it states this... As for the blur, it could be linked to CA's since it is black on white. Best bet would be to shoot in full manual mode anyways and set your shutter speed and ISO and then work your aperture and see what you get for blur on the house numbers. Actually looking again at your top pic of the houses, it looks like your focus is out in gfeneral... the rockwork and railing and everything is a bit fuzzy. were you using AF or maual focus? But you can definitely see the better color rendering of the K-r over the T2i, the Canon looks like it was sprayed with a matte finish, compared to the K-r's nice semi-gloss
I was using autofocus with the center spot.
03-20-2011, 05:12 PM   #11
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I'd suggest you check whether you have Ev adjusted (maybe to a +ve value?), and check what sort of metering you are using (matrix, center weighted, spot). Your friend may have been using -ve compensation or a different metering mode to you. I have the DA70 and it definitely does not have a tendency to over expose, I usually shoot at +0.3 or +0.7 comp with it.

I'm surprised the K-r is over exposing, I thought usually Pentax camera will tend to under expose compared to Canon.
03-20-2011, 05:13 PM   #12
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but i'm sure you can see yourself in the full shot compared to your friends that your focus is out. Try that shot again with manual focus if needed. In that bright of light I can't see the AF normally having problems, but that being said I don't think your camera has AF Fine tune to tweak each lens as the K-10/20/7/5 have. I found for my 43mm I had to adjust my AF Fine tune to get best results.
03-20-2011, 05:59 PM   #13
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I guess the general (mis?)conception is that Canon and/or Nikon is the baseline for everything about photography.

And I don't mean any offense here, it's just that those two are ahead of the pack, that naturally anyone one will think they are ahead for a reason, and any brand is just playing catch up.

About the subject, even if the variables are exactly the same, the difference in Canon and Pentax's light meters (which is influenced on the philosophy on how each brand would want to render a scene) may cause a slight difference in exposure settings.

That said any slight change in these variables (i.e. a light cloud covers 1/3 of the scene) may cause even two cameras of the exact same model with the exact same settings to meter differently.
03-20-2011, 07:00 PM   #14
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The OP may not realize that Canon (and Nikon) apply much greater sharpening in camera than Pentax does, as well as bumped up saturation and contrast at the default settings.
03-20-2011, 07:22 PM   #15
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there is AF fine tuning available on your K-r that you can play with too, but that won't help with your overexposing problem.
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