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09-17-2014, 08:47 AM   #16
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QuoteOriginally posted by rawr Quote
Spot metering mode may cause more problems than it solves. The spot isn't dynamic, just fixed in the centre of the frame, and furthermore only represents about 2% of the frame. If the spot drifts over a dark or light area, then your overall exposure is going to be very skewed.

As the manual says: 'Useful only when the subject is small'.

I'd stick to Multi-segment metering, or if you want to experiment, centre-weighted.

Are you using a hood?
Yes, using a hood, and a UV filter.

09-17-2014, 08:47 AM   #17
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QuoteOriginally posted by rawr Quote
Spot metering mode may cause more problems than it solves. The spot isn't dynamic, just fixed in the centre of the frame, and furthermore only represents about 2% of the frame. If the spot drifts over a dark or light area, then your overall exposure is going to be very skewed.

As the manual says: 'Useful only when the subject is small'.

I'd stick to Multi-segment metering, or if you want to experiment, centre-weighted.

Are you using a hood?
The fact that aperture is recorded as same but DOF is changing is hint of slow blades. Maybe that lens cannot keep up with 8fps?
09-17-2014, 08:49 AM   #18
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QuoteOriginally posted by charlestm Quote
Is there a setting that will lock the aperature during a continuous burst?
You could try either:

- AE-L with AF locked: 'locks the exposure value when focus is locked' - menu C1, item 4

or

- link the AE to the AF point (only works when using matrix metering) - menu C1, item 5.

Or just get very handy with the AE-L button

---------- Post added 2014-09-18 at 01:51 AM ----------

QuoteOriginally posted by charlestm Quote
...and a UV filter.
Eeeek! Give it a go minus that. With a hood it probably isn't necessary anyhow.
09-17-2014, 08:56 AM   #19
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QuoteOriginally posted by crewl1 Quote
There is a lever at the rear of the lens that you can move along the edge of the mount. When you move it the aperture blades should open and snap back when you let it go. If they are sluggish it may be they are binding somewhere.
Thanks for the quick tutorial on the lever. The aperature blades seem to snap back at a respectable speed.

09-17-2014, 09:00 AM   #20
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QuoteOriginally posted by charlestm Quote
Thanks for the quick tutorial on the lever. The aperature blades seem to snap back at a respectable speed.
I made this edit on my post above - I should state that I use focus priority so bursts are typically less than 8fps. Later today I can test using shutter priority and see if I get similar results to yours.


09-17-2014, 09:03 AM   #21
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Furthermore I notice you are still running v1.00 of the K-3 firmware.
The firmware is up to v1.11 now. Might be worth an update. There are some AWB fixes in there.

Latest K-3 Firmware Update : Software Downloads | RICOH IMAGING
09-17-2014, 09:06 AM   #22
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QuoteOriginally posted by rawr Quote
Furthermore I notice you are still running v1.00 of the K-3 firmware.
The firmware is up to v1.11 now. Might be worth an update.

Latest K-3 Firmware Update : Software Downloads | RICOH IMAGING
Ah, I did not know that. Will do asap. Thanks. I just got the camera a week ago.
09-17-2014, 12:20 PM   #23
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The images have the exact same exposure if you look at the exif. If the metering did something they would have different exif. Look at the spectators in the first and second image and you will see that in the second image there is more blur, i.e the lens is more open. I bet my left shoe that there is a problem with the aperture since the aperture on a Pentax is mechanical, not electronically controlled. Pull the lever and see if it is bent or if there is something obstructing it.

One thing to test is to put the camera in manual focus, use M-mode and set the shutterspeed to 1/800 and the aperture at f 7.1, look into the front end of the lens and burst away.

Does the iris/aperture close equally every time?

09-17-2014, 12:28 PM   #24
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QuoteOriginally posted by Tjompen1968 Quote
The images have the exact same exposure if you look at the exif. If the metering did something they would have different exif. Look at the spectators in the first and second image and you will see that in the second image there is more blur, i.e the lens is more open. I bet my left shoe that there is a problem with the aperture since the aperture on a Pentax is mechanical, not electronically controlled. Pull the lever and see if it is bent or if there is something obstructing it.

One thing to test is to put the camera in manual focus, use M-mode and set the shutterspeed to 1/800 and the aperture at f 7.1, look into the front end of the lens and burst away.

Does the iris/aperture close equally every time?
I pulled the lever, and the aperature opens and closes easily. I don't see an obstruction, at least not an obvious one. However I will try your experiment with M-mode and report back. Thanks.
09-17-2014, 02:57 PM   #25
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does the K3 have 2 continuous shooting modes? try it in slow instead of fast, and i'd be willing to bet the problem goes away. More evidence pointing to the aperture being somewhat sluggish. Maybe not enough to see with your eye, but makes a difference at 8fps
09-17-2014, 06:04 PM   #26
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QuoteOriginally posted by Tjompen1968 Quote
The problem you have is that the lens does not stop down.
Yep

QuoteOriginally posted by charlestm Quote
With an HSM lens, all of the mechanics are inside the lens, so you don't see anything move, correct?
Nope, not with Pentax. The amount of stop-down is fully mechanical and is supposed to be determined by the amount of deflection of the actuator lever. It is possible that your lens has a "lazy aperture" meaning that it is slow to stop down or is binding. Do you have this issue with lenses other than the Sigma 70-200?


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09-18-2014, 01:16 PM   #27
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This isn't directly germane to the OP's issue but when you are shooting sports, unless the "field of play" is unevenly lit in a dramatic way, manual exposure is the best bet. I always use manual when shooting sports. For events on a grass field, I meter off the grass itself—just about a perfect midtone for the metering system. This even works well for night events (football, baseball etc) and keeps the camera from reacting to momentary dark or light influences. For indoor venues, a gray card is appropriate. Using manual settings eliminates any thinking the camera has to do while trying to keep up. And, it will make it easier to determine if a problem is mechanical.
09-22-2014, 08:38 AM   #28
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First, let me thank all of you for the advice. I spent the last week shooting more soccer games and experimenting with all of the suggestions offered here in this thread.

Long story short (and maybe some of you can explain why this worked), the continuous shooting issue disappeared.

Some of you thought that the aperture on the lens was slow to respond, but I put the lens on the K-7, and the continuous shooting issue did not surface on the K-7 (but remained on the K-3). Note that I updated the firmware on the K-3, but that did not solve the continuous shooting issue.

So, I did a factory reset of the K-3, put this same lens back on the K-3, and I used only these setting changes:

* multi-segment metering
* switched to AF.S (from AF.C originally)
* AF active area of Auto 27 AF Points
* TAV mode (with ISO range of 100-3200)
* JPG
* #15 AF.S Setting = 1
* #18 AF Status = 3 (medium)
* SR = on
* AF Button - AF1 Enable (meaning not using the AF back button)
* Shutter 1/800
* Aperature 5.0

The photos from yesterday's shoot were great .... crisp, clear .... and most importantly, the sequence bursts were all consistent in terms of exposure.

I have attached a sequence of 3 un-edited photos from a burst.

Also, if you want to see the entire edited shoot: Womens PSU GA vs Point Park - original photography by data blueprints

I took about 300 shots, and 100 were keepers, so that's a pretty good ratio.

Thanks again to all who helped .... I'm still not sure why this worked, so if you want to comment on that, please do.

Chuck
Attached Images
 
09-23-2014, 08:36 AM   #29
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Good news! However I suspect the problem maybe just hiding. The aperture control mechanism in K3 is a lever. It can malfunction sometimes. How many shutter actuations on your K3? I know it is rated for 200K. But thats the same thing as car manufacturers claiming 35 miles per gallon regardless of other variables.
09-23-2014, 11:13 AM   #30
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I would guess whatever was keeping the lens from stopping down was fixed when you tinkered with it. Maybe it just needed to have the lever jurked or maybe only getting the lens off and on again fixed it. A strand of hair or a small spec of dust in the wrong place... Maybe the temperature was colder so that the oil in the aperture got sluggish...

It is obvious that the aperture has not been the same in the first and following photos since the DOF is shallower in the second and third image. Still the camera thinks it is and therefor keeps the ISO at the same level.

---------- Post added 09-23-14 at 08:18 PM ----------

Also this time you are using f/5.0 instead of f/7.1. This may have an impact. Try f/8 or 11 and see if it differs.
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