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Old Mar 15, 2006, 9:05 AM   #21
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To support your theory Jim, it IS actually a 3rd party lens, my Minoltasaw its last leg a whileback. So it seems like my best solution right nowis to test out my 50mm lens for portraits andI should begetting better results that way.I'm going to try that out this afternoon, hopefully that'lldo the trick.
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Old Mar 15, 2006, 9:15 AM   #22
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Most of the lenses in that range (28-80mm) with that brightness (f/3.5-5.6) are going to be a bit soft shooting at wide open apertures (and you were shooting at the widest available aperture).

That may not be your entire problem. It could be an AF calibration problem as others have mentioned, or it could be something else.

But, the lenswould be my first suspect since you shot at the widest available aperture, combined with the possibility of some blur from subject movement, and possibly loss of focus if you lockedfocus with a half press while the subject was moving towards you).

I'd try the 50mm f/1.7 at around f/2.8 or f/3.5 (which would get your shutter speeds up to about twice as fast as you were shooting at in the same lighting at the same ISO 400 setting). I'd lock focus on asubject's eye.

You can shoot in Av (Aperture Priority Mode) and spin the control wheel until you see it in the viewfinder, or shoot in P (Programmed Auto) mode and do the same thing (spin the dial to change between aperture/shutter speed combinations).

Then, if you have depth of field problems, try it at f/4 instead (which will be even sharper at the loss of some shutter speed if you stayed at ISO 400, but still faster than you were getting in the same lighting with the other lens).
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Old Mar 15, 2006, 9:29 AM   #23
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Geez Jim, why you beating down my lens like that?:blah:

BTW, I accept your challenge- I will find and buy a poorer lens. (In fact, I have been considering oneof those 28-300 zooms...)

Darlene, that 50mm 1.7 is a near perfect portrait lens. I am not so dissatisfied with my 28-80 as Jim would suspect. But then, my eye may not be quite as critical as his. I'm satisfied with it for the use it gets, family reunions, day trips and such.
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Old Mar 15, 2006, 9:40 AM   #24
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Mercury694 wrote:
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Geez Jim, why you beating down my lens like that?:blah:
Sorry about that. ;-) I was just looking at scientific MTF tests, along with opinions of users that have it and passing on the info.

Yes, it may not be too bad for most uses. But, I wouldn't want to try shooting portraits with it at wide open aperturesunless I was going for a soft look (especially at the camera's default sharpening setting). LOL

Her 3rd party lens may be sharper from the looks of opinons on the Minolta 28-80mm f/3.5-5.6

I'll tell you what though... I've been impressed with my Minolta 24-85mm f/3.5-4.5 shoooting pretty close to wide open with it (and it's an inexpensive lens on the used market). It also tests sharper wide open, compared to the 28-80mm stopped down.Center sharpness is sweet (it's a little softerin the corners):-)

http://www.photodo.com/prod/lens/det...5-45-371.shtml

The 35-70mm f/4 I recently got is a very inexpensive lens that produces good results, too (but, I haven't test it wide open yet, only down a stop at f/5.6).

But, for portraits (especially in existing light), I'd be using a prime.

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Old Mar 18, 2006, 12:44 AM   #25
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Darlene,

Definitely sharpen up your camera by 1 step. that's the first thing I did when I received it. Defaults tend to be a little soft. And I am not sure about the lens you use. The kit lens works fine with +1 in the sharpening.

Here is a shot I took. Looks fine to me.


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Old Mar 19, 2006, 7:10 PM   #26
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bernabeu wrote:
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set sharpness to +1

(not sure on 5D, i have 7D) set color to natural+

TEST THE AF WITH THE 50mm f1.7 and a yardstick at 45 degree angle at about 3' distance -> use center spot focus and f1.7 with tripod
What is the tolerance for this measurement? According to http://www.dofmaster.com/dofjs.html, thedepth of field forthe KM5D for the configuration you noted is:.03ft (1/33 inch)in front of subject and .04ft (1/25 inch) behind subject. Would anything outside of that be a significant error?

Using the setup and settings you recommended, I found a bit of front focus on my 5D. I observedthe middle of the in-focus area at 1/2-3/4 inch on the angle yardstick (angled at 45degrees) from the aimed spot focusing point.This corresponds to1/4 to 3/8 inch closer to the camera. This is well beyond the sharpness rangecalculated.

The point I aimed the spot focus at was only slightly soft. Of course, I'm looking for all the sharpness the KM can provide.Would it help to link to a high resolution picture to discuss the matter?

Thanks in advance,

Scott
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Old Mar 19, 2006, 10:13 PM   #27
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Scott, here is another expample of the sharpness the KM5D provides. This was taken in Natural Mode with +1 sharpening. I used a Sigma 75-300, 4.0-5.6 lens at about 200 mm. Exif data shows, this shot was taken at 1/640 second, 7.1 aperture at ISO 100.I spot focused on the eye which one definitely wants to dowith animal shots as well as inportraits of humans.This picture makes for a gorgeous and crisp 8.5x11 print, by the way. It is VERY sharp even if blown up. So I hope that between the tips you got on which aperture to use, how to focus, and which in camera sharpening settings to use, you should get good results.

Sure send a link to a full sized image. I'd love to do more troubleshooting.


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Old Mar 19, 2006, 11:38 PM   #28
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rduve,

That's encouraging toseewhat a nice picture is possible with the KM5D. I am new to dslrs' and have learned much studying the recommendations by experienced photographers on these forums,especially KM DSLRowners .

My presentobjective is to make sure that myKM5D is working properly. JimC helped mediagnose a Front Focus problem earlier.Focusing was greatly improved byreplacing the only lens I had at the time.I thought the FF problemwas entirely solved. (For the gory detailssee thread: http://www.stevesforums.com/forums/v...mp;forum_id=87)

My experience since changing the lensmakesmewonder if therestill is a bit of a FF problem.Thefocus test with the yardstickseems capable of identifying smaller focusingerrorsthan the methodI previously used.

I have to figure out how to link a high-res photo.

Thanks for the input.

Scott
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Old Mar 20, 2006, 7:37 AM   #29
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Magnum,

the DOF is irrelevant

the actual focus point of the camera should precisely correspont to the aimed focus point

eg. if the center (AF) spot was on the 18" mark -> the 18" mark should be razor sharp (the 50mm f1.7 is used by KM to calibrate)

if it does not, send the camera to KM for calibration

i had my 7D for 11 months with not quite perfect results until i tested it myself and sent it in for calibration -> now get razor sharp images straight from camera

...john

ps. focus was on bird's eye


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Old Mar 20, 2006, 8:32 AM   #30
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Magnum wrote:
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My presentobjective is to make sure that myKM5D is working properly. JimC helped mediagnose a Front Focus problem earlier.Focusing was greatly improved byreplacing the only lens I had at the time.I thought the FF problemwas entirely solved. (For the gory detailssee thread: http://www.stevesforums.com/forums/v...mp;forum_id=87)

My experience since changing the lensmakesmewonder if therestill is a bit of a FF problem.
Scott:

You really need to use a prime to check out the camera to see if it's got an issue. You're going to see more variation between copies of zoom lenses.

Quotes from the original thread where you had a suspected problem:


Quote:
Make sure it's not the camera body. Use a bright prime like a 50mm f/1.7 and see how it works. If it's backfocusing or front focusing with a good prime, it's the camera. If not, it's probably the Tamron.
Quote:
KM uses a 50mm f/1.7 for AF alignment purposes, since a good prime is going to be much sharper than a zoom lens, has larger available apertures making AF problems easier to discern, and doesn't suffer from barrel or pin cushion distortion like you'd have with a zoom lens. A "normal" focal length prime (like a 50mm), will also have a more even focus plain across the frame compared to a zoom lens.

If the camera is not backfocusing or front focusing with a good prime, then it could be a lens issue causing that much softness. If so, I'd see if the dealer will swap it out, or you can send it back to Tamron for them to check it out.

Or, if it's a camera problem, see if the dealer will swap it out (or you can send it to KM for alignment).
Quote:
A prime is recommended for this type of testing, too (a zoom lens has a lot more distortion, depending on focal length). KM (at least in the U.S.) uses a 50mm f/1.7 for aligning AF sensors.

Make sure to use a tripod (if you lean after locking focus, you'll skew the results), and make sure you're selecting a sensor in the center of your target and you're getting a focus lock (steady versus blinking green light).

If a 50mm prime behaves the same way, then it's most likely a camera problem. If it works fine and the zoom doesn't then it's most likely a lens issue.
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