Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-01-2013, 07:29 AM   #16
Pentaxian
hnikesch's Avatar

Join Date: May 2009
Location: Michigan, USA
Photos: Albums
Posts: 1,254
QuoteOriginally posted by excanonfd Quote
They definitely are action shots even if they are not all that sharp. The 3rd shot of the horse with it's nostril flaring is the sharpest. I do understand the point you are making - the genuine adapter with built-in shutter can only improve upon the image making process.
True they leave a lot to be desired in sharpness but tracking motion and manual focus using a 750mm lens this was the best I could do. I used my Kr with 55-300 for my serious shots of the event, I just wanted to see what the Q could do.

Hans

04-01-2013, 09:46 AM   #17
Veteran Member




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
Original Poster
QuoteOriginally posted by hnikesch Quote
True they leave a lot to be desired in sharpness but tracking motion and manual focus using a 750mm lens this was the best I could do. I used my Kr with 55-300 for my serious shots of the event, I just wanted to see what the Q could do.

Hans
If you could re-shoot these type of sporting events over again with the genuine adapter, I would be real interested in the resulting images. I agree, it's quite incredible what you were able to do with a 750mm equivalent lens, inducing jelly effect doesn't take much at all with telephoto lenses.
04-01-2013, 11:31 AM - 3 Likes   #18
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,797
Extreme Q shutter test. Lens used on adapter FA50. Ignore white balance, irrelevant for this test. Thanks for making me clean my fan.

Pentax adapter at 1/1000 max leaf shutter speed


Pentax adapter at 1/1250 using electronic shutter


Pentax Q 02 lens at 1/2000 max leaf shutter speed


Pentax Q 02 lens at 1/2500 using electronic shutter
04-01-2013, 12:50 PM   #19
Pentaxian




Join Date: Oct 2006
Location: Chicago suburb, IL, USA
Posts: 1,535
QuoteOriginally posted by crewl1 Quote
Extreme Q shutter test. Lens used on adapter FA50. Ignore white balance, irrelevant for this test. Thanks for making me clean my fan.

Pentax adapter at 1/1000 max leaf shutter speed


Pentax adapter at 1/1250 using electronic shutter


Pentax Q 02 lens at 1/2000 max leaf shutter speed


Pentax Q 02 lens at 1/2500 using electronic shutter
Hi Larry,

Very Cool!

I'm going to have to do some thinking of how it might be possible to use the rolling shutter purposefully as an effect.

Scott

04-01-2013, 02:03 PM   #20
Veteran Member




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
Original Poster
QuoteOriginally posted by crewl1 Quote
Extreme Q shutter test. Lens used on adapter FA50. Ignore white balance, irrelevant for this test. Thanks for making me clean my fan.

Pentax adapter at 1/1000 max leaf shutter speed


Pentax adapter at 1/1250 using electronic shutter


Pentax Q 02 lens at 1/2000 max leaf shutter speed


Pentax Q 02 lens at 1/2500 using electronic shutter
Thanks Larry for the shots, any idea what the fan's rpm might be? Quite the funky looking blades when shot with electronic shutter.
04-01-2013, 02:20 PM   #21
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,797
QuoteOriginally posted by excanonfd Quote
Thanks Larry for the shots, any idea what the fan's rpm might be? Quite the funky looking blades when shot with electronic shutter.
If my Tower Hobbies RC airplane tach is correct the blades are running at average 2300 RPM . Not sure how accurate it is.
04-01-2013, 02:35 PM   #22
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,797
QuoteOriginally posted by snostorm Quote
Hi Larry,

Very Cool!

I'm going to have to do some thinking of how it might be possible to use the rolling shutter purposefully as an effect.

Scott
Right? It was surprising that it broke them up like that.
04-01-2013, 02:38 PM   #23
Pentaxian
panoguy's Avatar

Join Date: Sep 2007
Location: Washington, D.C.
Photos: Gallery | Albums
Posts: 3,290
I just tried shooting my fan with the leaf vs. electronic shutter... looks the same!



(FYI: it's April 1st)

04-01-2013, 03:02 PM   #24
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,797
QuoteOriginally posted by panoguy Quote
I just tried shooting my fan with the leaf vs. electronic shutter... looks the same!



(FYI: it's April 1st)
Ha Ha!
04-01-2013, 05:20 PM   #25
Pentaxian
arnold's Avatar

Join Date: Aug 2012
Location: Queensland
Photos: Gallery | Albums
Posts: 3,295
Let me get this straight. Is it being said that the exposure time OF the sensor is not the exposure time TO the sensor? That, regardless of set shutter speed, the sensor is exposed for 1/13 sec? That electronic shutter speed does not change the time the sensor is active, but changes it's sensitivity (ISO)? That every picture is exposed to movement for 1/13 second?
04-06-2013, 04:28 PM   #26
Veteran Member
ChrisJ's Avatar

Join Date: Nov 2008
Location: Eckington, Derbyshire UK
Photos: Gallery | Albums
Posts: 316
QuoteOriginally posted by arnold Quote
Let me get this straight. Is it being said that the exposure time OF the sensor is not the exposure time TO the sensor? That, regardless of set shutter speed, the sensor is exposed for 1/13 sec? That electronic shutter speed does not change the time the sensor is active, but changes it's sensitivity (ISO)? That every picture is exposed to movement for 1/13 second?
Shutter speed and scan time are two different things.

Scan time is the time the camera takes to scan the RGB values of every one of the 12 million pixels and send them off to the A/D converter. All digital sensors work this way. Normally on stills cameras there is a mechanical shutter which stops light from hitting the sensor during the scan time, when there's not then the pixels are still active and still changing values during this scan time.

I don't know if the relatively slow scan time is because of the speed of the chip or the speed of the processor in the Q, either or both can cause this problem.

There is less of this problem in video mode as then your only scanning 2 million pixels per frame which can be done in 1/78th (1/13th * 6) of a second or so.

The sensitivity of each pixel is set by the camera, one of the pins on all sensors sets this by varying a voltage (tiny differences make big changes). The cameras interface shows this voltage adjustment as a varying shutter speed.

This is not the same as ISO which just raises or lowers the overall voltage to the sensor to increase or decrease the overall sensitivity of the chip, but at the expense, when higher, of more heat and more spurious noise generated by the sensor itself. Again the cameras interface translates this into faster or slower shutter speeds.

Chris
04-06-2013, 05:56 PM   #27
Pentaxian
arnold's Avatar

Join Date: Aug 2012
Location: Queensland
Photos: Gallery | Albums
Posts: 3,295
QuoteOriginally posted by ChrisJ Quote
Shutter speed and scan time are two different things.

Scan time is the time the camera takes to scan the RGB values of every one of the 12 million pixels and send them off to the A/D converter. All digital sensors work this way. Normally on stills cameras there is a mechanical shutter which stops light from hitting the sensor during the scan time, when there's not then the pixels are still active and still changing values during this scan time.

I don't know if the relatively slow scan time is because of the speed of the chip or the speed of the processor in the Q, either or both can cause this problem.

There is less of this problem in video mode as then your only scanning 2 million pixels per frame which can be done in 1/78th (1/13th * 6) of a second or so.

The sensitivity of each pixel is set by the camera, one of the pins on all sensors sets this by varying a voltage (tiny differences make big changes). The cameras interface shows this voltage adjustment as a varying shutter speed.

This is not the same as ISO which just raises or lowers the overall voltage to the sensor to increase or decrease the overall sensitivity of the chip, but at the expense, when higher, of more heat and more spurious noise generated by the sensor itself. Again the cameras interface translates this into faster or slower shutter speeds.

Chris
Thanks for this explanation; I am still trying to absorb it. How does a high shutter speed have any meaning if the scan time determines the actual exposure time? Is the high shutter speed only a factor of sensitivity of the sensor and not, as I originally thought, the time the sensor was switched on to transmit the exposure?
04-07-2013, 06:11 AM   #28
Loyal Site Supporter
drougge's Avatar

Join Date: Jan 2010
Location: Malmö
Photos: Gallery
Posts: 787
QuoteOriginally posted by ChrisJ Quote
The sensitivity of each pixel is set by the camera, one of the pins on all sensors sets this by varying a voltage (tiny differences make big changes). The cameras interface shows this voltage adjustment as a varying shutter speed.

This is not the same as ISO which just raises or lowers the overall voltage to the sensor to increase or decrease the overall sensitivity of the chip, but at the expense, when higher, of more heat and more spurious noise generated by the sensor itself. Again the cameras interface translates this into faster or slower shutter speeds.
That's just plain wrong.

The shutter speed you set determines how long each pixel collects photons. When you have a shutter each pixel starts collecting at the same time and then when the shutter closes they can be read out slowly with no problem.

When you don't have a shutter the shutter speed still determines how long each pixel collects photons, they are just not started at the same time. If you set 1/1000 as the shutter speed the pixel is switched on 1/1000s before it will be read out. The time it takes to read out the whole sensor doesn't matter for this, it only affects how long the time is between the pixels being turned on.

ISO works as if it worked like you describe, though I doubt it's done through analog means on modern sensors. Except for the last sentence, which I'm not sure what it means. Changing the ISO doesn't change anything else unless the camera is in an automatic mode.
04-07-2013, 06:43 AM   #29
Pentaxian
hnikesch's Avatar

Join Date: May 2009
Location: Michigan, USA
Photos: Albums
Posts: 1,254
QuoteOriginally posted by drougge Quote
When you don't have a shutter the shutter speed still determines how long each pixel collects photons, they are just not started at the same time. If you set 1/1000 as the shutter speed the pixel is switched on 1/1000s before it will be read out. The time it takes to read out the whole sensor doesn't matter for this, it only affects how long the time is between the pixels being turned on.
Now this explanation makes more sense to me, as I was able to stop motion of a baseball traveling @ 90 MPH with my shutterless adapter @ 1/3200 sec. Now the 1/13 sec.or more flash sync time must be the shortest duration that has all the rows of sensors capturing light at the same time.

Hans
Attached Images
View Picture EXIF
PENTAX Q  Photo 
04-07-2013, 09:51 AM   #30
Veteran Member
steve1307's Avatar

Join Date: Mar 2010
Location: Sydney
Photos: Gallery | Albums
Posts: 1,129
QuoteOriginally posted by hnikesch Quote
Now this explanation makes more sense to me, as I was able to stop motion of a baseball traveling @ 90 MPH with my shutterless adapter @ 1/3200 sec. Now the 1/13 sec.or more flash sync time must be the shortest duration that has all the rows of sensors capturing light at the same time.

Hans
Ok i get it, so each pixel is only reading for 1/3200s each, but it takes 1/13s to make a sweep of all 12million of them.

Lets assume that it starts scanning in rows from the top left across the pixels in the row and then down to the next row left to right scanning across each row and down to the next row until it gets to the bottom right corner 1/13 s seconds after it started the first pixel.

Fast moving objects would get distorted if parts of them were scanned with some delay.

The ball going at 90mph is moving fast but since it is small (number of pixel rows) is few and the delay in scanning the top part of the ball and the lower section of the ball is negligible so no distortion.

In this shot the Batter probably didn't attempt swing his bat as the Pitcher sent the ball down near his ankles but I wonder if the the batter did swing his long bat then would it look "curved" or distorted due to the scan time if it was vertical?



The same sort of thing happens with mechanical shutter DSLR's but the shutter takes a bit less than 1/180s to cross the entire frame.
The shutter curtains move downwards exposing only a narrow slit for faster shutter speeds but they still take 1/180s to travel from the top to the bottom.
Next time you're in a propeller engined aircraft take a picture of the rotating propeller blades at maybe 1/4000 or 1/6000 or 1/8000s and you can "freeze" them but they look curved. when in reality they're straight.
Same rolling shutter effect but since the DSLR mechanical shutter is 180 /13 = 14times faster than the Q electronics scan so the effect is less.
The scan speed of live-veiw is much slower so if you look at the propeller blades through liveview LCD they look like they're detatched like crew1's fan shots above.

.
so which one?.....
.
I think I'd probably go for the $250 Pentax one with the shutter....... but only tell the wife i'm looking at the $40 ebay ones.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
adapter, camera, fan, image, mirrorless, pentax q, pentax q10, pentax q7, q10, q7, shutter
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Genuine Pentax Mount Adapter B or M42 To K adapter SANDY1977 Pentax Camera and Field Accessories 9 06-22-2013 02:41 PM
Pentax Q / adapter K to Q / DA 35mm f2.4 AL wax Pentax Q 4 11-06-2012 02:55 AM
For Sale - Sold: GEnuine Pentax m42 to K adapter 30120 dcshooter Sold Items 3 11-01-2012 09:20 AM
For Sale - Sold: Pentax Genuine m42 to K adapter dcshooter Sold Items 3 05-31-2012 07:44 PM



All times are GMT -7. The time now is 05:13 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top