Why I don't think we'll ever see IBIS

[dsingley]

Most of the Pentax DSLRs IBIS. With a built in GPS (e.g., K -1) or the GPS accessory (e.g., K-70) allows for astrophotography w/o having to invest in an equatorial Mount or exposure limitation based on focal length. 3 min exposure 30mm FF equivalent. K-70.

View attachment 186909

Hmmmm, whats interesting here is that the moving part is still but the still portion, the ground, has blur?!?! SS

In defense of the image, this was only the third time or so that I had tried this, so my technique was probably not the greatest. I was more interested in capturing the Milky Way than the unremarkable beach in the foreground. Also, there was a fair amount of wind - enough to make me think that my tripod might not be up to the task. Used ISO 800. In my experience with the K-70, ISO 800 does not generate much, if any, noise. Probably could have gone to 1600 without much noise penalty - rookie mistake. Interesting foot note, I made a field expedient center weight for the tripod from a plastic grocery bag (stuck in my jacket pocket against the potential need for a center weight) and sand from the beach on which I was standing.

 

[TWX]

Most of the Pentax DSLRs IBIS. With a built in GPS (e.g., K -1) or the GPS accessory (e.g., K-70) allows for astrophotography w/o having to invest in an equatorial Mount or exposure limitation based on focal length. 3 min exposure 30mm FF equivalent. K-70.

View attachment 186909

Hmmmm, whats interesting here is that the moving part is still but the still portion, the ground, has blur?!?! SS

In defense of the image, this was only the third time or so that I had tried this, so my technique was probably not the greatest. I was more interested in capturing the Milky Way than the unremarkable beach in the foreground. Also, there was a fair amount of wind - enough to make me think that my tripod might not be up to the task. Used ISO 800. In my experience with the K-70, ISO 800 does not generate much, if any, noise. Probably could have gone to 1600 without much noise penalty - rookie mistake. Interesting foot note, I made a field expedient center weight for the tripod from a plastic grocery bag (stuck in my jacket pocket against the potential need for a center weight) and sand from the beach on which I was standing.

Better than I'd have gotten on my first goaround. I'd probably be dragging my laptop out with me to review what I'd gotten in the truck between numerous shots, probably taking quite a bit of time to get the settings right, if not outright shooting tethered.

 

[JBPhotog]

Most of the Pentax DSLRs IBIS. With a built in GPS (e.g., K -1) or the GPS accessory (e.g., K-70) allows for astrophotography w/o having to invest in an equatorial Mount or exposure limitation based on focal length. 3 min exposure 30mm FF equivalent. K-70.

Umm me thinks you are mistaken about the "w/o having to invest in an equatorial Mount". Built in GPS is only for geotagging the photos so you can use that data to see where you took the photo when you upload them to either Google Maps, Google Earth or any other map software that accepts geotags. Most DSLR's will accept a Bluetooth dongle which can communicate to a GPS data logger to achieve this function however, many cameras are now being offered with built in GPS for this purpose. I'm not sure how a focal length can limit exposure, most cameras have a 'Bulb' setting which allows you to keep the shutter open as long as you want. Focal length is not one of the exposure parameters in which to achieve correct exposure, ISO, shutter speed and F-stop are.

Your photo clearly shows camera shake from an unstable platform, likely your deduction of the wind and a less than stable tripod. There are methods to mitigate this you may want to explore.

In fact here is the geotag info from your star photo:

 

[dsingley]

The Pentax IBIS allows for longer exposures w/o star trails. The system, as I understand it, uses either the built in GPS, or the attachable GPS (which is what I had on my K-70), to figure out, with the focal length of the lens attached, how long the shutter can be open before the trails start to form and then, using a cable release, will open the shutter for that length of time - no 30 sec. limit. I agree, the focal length is not relevant to the exposure, just how long the shutter can stay open w/o forming a star trail (and, of course composition). Some might say that all I did was pay the price of the GPS accessory to math (i.e., divide 500 by the FF equivalent of my len’s focal length), something I could likely have done in my head - to a reasonable degree of precision, or used the calculator function on my smart phone to do to a greater degree of precision. I would not suggest that the IBIS/GPS combo is a full substitute for an equatorial Mount because there is a limit to the sensor’s ability to move, thus there is an upper limit on exposure length - before trails start to form. Also, I don’t know if one can stack (other than in post processing) using the Pentax GPS/IBIS system to gather the light necessary to capture more distant or small objects. For those of us on a budget, though, it is helpful for some night sky photography.

 

[petrochemist]

@JBPhotog you need to have another look at the image. The stars do NOT show movement, the blur you can see is from foreground lights which are not moving across the sky with the stars. A motorized equatorial mount would show just the same effect.
Pentax's Astrotracker doesn't use the 500 rule, it works out precisely how to move the sensor based on location & direction faced to correct for the earth rotation. It doesn't allow as long an exposure as a dedicated tracker, but IIRC does give an order of magnitude to the exposure before star movement is apparent. I don't think any other IBIS system offers this function. GPS location alone is pretty much meaningless for this, the Pentax O-GPS needs more precise details gathered via a calibration procedure (involving rotating the camera through each plane in turn) before the Astrotracker option can run. The first O-GPS module I got refused to do the calibration & it's compass never functioned even moderately well (moss on the side of trees was more accurate!). Fortunately I was able to find someone wanting GPS without the compass/astrotracker & the guy I brought the O-GPS from refunded the difference in price. Perhaps one day I'll have another go...

 

[JBPhotog]

@JBPhotog you need to have another look at the image. The stars do NOT show movement, the blur you can see is from foreground lights which are not moving across the sky with the stars. A motorized equatorial mount would show just the same effect.
Pentax's Astrotracker doesn't use the 500 rule, it works out precisely how to move the sensor based on location & direction faced to correct for the earth rotation. It doesn't allow as long an exposure as a dedicated tracker, but IIRC does give an order of magnitude to the exposure before star movement is apparent. I don't think any other IBIS system offers this function. GPS location alone is pretty much meaningless for this, the Pentax O-GPS needs more precise details gathered via a calibration procedure (involving rotating the camera through each plane in turn) before the Astrotracker option can run. The first O-GPS module I got refused to do the calibration & it's compass never functioned even moderately well (moss on the side of trees was more accurate!). Fortunately I was able to find someone wanting GPS without the compass/astrotracker & the guy I brought the O-GPS from refunded the difference in price. Perhaps one day I'll have another go...

Huh? BTW, I did have a look at the image and I see star trails, I suggest you may want to check the corners since this area of the lens will show the greatest movement.

You will also see blur or ghosting next to the star trail which could also be due to the wind factor.

 

[fotografdenunta]

Ibis will certainly appear in the next canon r5. They announced it so... fingers crossed!