Web Analytics RiceHigh's Pentax Blog: Pentax O-GPS1: The SR Systems of the K-5 and K-r are Different!

Sunday, June 05, 2011

Pentax O-GPS1: The SR Systems of the K-5 and K-r are Different!



http://www.pentax.jp/english/news/2011/201107.html

Look at the summary table of the Astrotracer part, we see that the tracking time when the O-GPS1 is used with a K-5 and a K-r are somehow different:

[ ASTROTRACER Tracking Time (approx. in sec.) ]
K-5
DeclinationFocal Length
(°)200mm100mmunder 50mm
90300300300
45160290300
0110240300
K-r
DeclinationFocal Length
(°)200mm100mmunder 50mm
90300300300
4580200300
080170300

So, it simply hints that the order of magnitude for the allowable movement of the K-5 and K-r SRed sensors are different. Practically, the larger order of magnitude of the K-5's SR system should allow it to make corrections for more hand shake errors and particularly for the use of longer focal length lenses, theoretically and provided that the other parts of the SR (feedback) system can also cope with.

Update (6-8): For more detailed information of the O-GPS1, you can read this product page (Google translated, original in Japanese).




Related:-

What are These Pentax Big Guns?

Comments (18)

Loading... Logging you in...
  • Logged in as
Pentaxian's avatar

Pentaxian · 709 weeks ago

It's not necesarily due to SR itself, the K-r has less MP with the same sensor size, so a one-pixel shift would be more µm on the K-r than on the k-5(?)
1 reply · active less than 1 minute ago
Not really. The resolution difference should be a don't care case here. I am almost sure that it should be the difference between the SR systems.
So they are different. What's the point?
PARTIAL REPOST:

I have bought an O-GPS1 and I am fascinated by the perfectionism that was involved in the creation of this unit:

(i) the user interface could not be simpler - the firmware behaves as if the device was integrated in the camera body

(ii) not only GPS coordinates but also shooting direction is stored in the pictures, plus the camera automatically detects the universal time (UTC) and even the time zone. In other words, this unit is utilizing the GPS idea to the maximum extent possible.

(iii) wonderful extra feature "simple navigation", may be useful to exactly come back to a location where an image was shot previously, e.g. if you want to take exactly the same landscape shot one year later.

(iv) very innovative special feature for astrophotography: ASTROTRACING, a perpetual Xmas for us night sky photographers. This is an integrated "virtual equatorial mount", making the K-5 the first camera in the world that can do sharp bulb shots of the night sky without the need for a separate, heavy and complicated externally-driven mount that compensates for the rotation of earth.

Remark: this last feature CANNOT be matched by even the most expensive Nikon, Canon, Sony or Olympus camera because none of those has a movable sensor (their shake reduction mechanism relies on prisms inside the LENS not the body, and by construction these cannot correct for rotations).

C
14 replies · active 701 weeks ago
Sony/Minolta and Olympus had sensor-shifted anti-shake technology for long.
But to my knowledge, no sensor rotation. And that is what is needed for Astrotracing.
Yep - just double-checked my claim on the respective web-sites, and it is correct:

For the reason I gave above (key differences in the SR mechanism), ASTROTRACING is and will remain a PENTAX-ONLY feature! The competition will not be able to copy it.

Now isn't that something to write about? Pentax leading the industry once again!

Admittedly Astrotracing may appeal only to a small fraction of photographers, but that may be the kind of active, outdoor photographer Pentax is targeting anyway. Speaking for myself, I'm 42 years old, and when vacation-travelling, I still spend many nights in a tent. Starting now, I will be able to make night sky pictures from that very tent with no extra equipment and little know-how involved.
1. Since you do not comment on Olympus, we seem to agree there.

2. On Sony/Minolta, the linked blog entry compares PATENTS, while I am referring to PRODUCTS. Patents describe inventions, while product brochures and marketing websites describe products.

Read this: http://www.sony.net/SonyInfo/technology/technolog... . A quote: "The image stabilization unit contains two actuators to correct camera-shake in two directions: pitch and yaw." That is what I said and meant: For a third degree of freedom, the IS unit would have to be redesigned completely.

Result: Astrotracing will remain a Pentax-only feature because all other manufacturers would have to re-think their whole image stabilization technology. The Pentax technology proves superior here.
Products are made based on patents. Yaw and Pitch (=x&y) makes rotational movement also possible. There is no additional degree of freedom for the Pentax system. The compensation is restricted to a plane, i.e., 2D only.
Rice -
you are an engineer. Have you ever applied for a patent, and have you developed products trying to avoid features that were patent-protected by competitors?

When was the last time a patent described exactly the product you made?

When was the last time somebody put a patent on your desk and told you "make a product like this"?

I have been working for many years as a managing director in a high-tech precision engineering company (development and manufacturing) with a company focus on mechanics but also electronical devices.

I do not recall a single instance where the final product was really accurately described by the patent. And that makes sense for a variety of reasons. Also, products are NOT made "based on patents". There are products based on _inventions_, but not every product includes a new invention, and some combine several ones. In my experience, products are developed based on product ideas, specs based on market research and so on. Patents - if there are such - are usually de-coupled from development in an EARLY stage (to catch an early priority date for the patent) and very often DO NOT describe the final product, which may be better (due to further development) or worse (due to cost issues or patents of competitors) than the patent description.

Secondly, Yaw and Pitch (TWO degrees of freedom) explicitly rule out rotation (that would be the THIRD degree of freedom). I am a physicist by education, trust me that is how degrees of freedom are counted. If you still don't believe me, click on the link to Sony that I have quoted, you will find an animated picture that shows X and Y motion but does not show rotational motion. Why would they not show it (in a promotional web site) if the product had it?

Thirdly, put another way: if Sony's IS mechanism really matched Pentax' principle, then Sony's marketing department is clearly missing a point here. So much on the quality of marketing departments (another issue you brought up recently as a criticism of Pentax...).

Rice, there are issues on which you point out a problem correctly. This time, you are wrong.
...another attempt to explain it: In 2D, the position and orientation of a sensor is described by THREE numbers (X, Y, and an angle). Since Sony's IR allows for motion in TWO dimensions (X and Y), sensor rotation is NOT possible, thus no astro-tracing possible.

I am willing to bet you that Sony, Olympus, Nikon and Canon will NOT incorporate astro-tracing in any of TODAY's EXISTING DSLR bodies within the next 5 years. Are you willing to bet against this?

(we need to agree on what's at stake. What about this: Whoever loses sends an FA* 85/1.4 to the other. Ok?)
The Sony marketing sheet and the Minolta patent does agree with each other. The information sheets both show that the "sliders" mounting the sensor are moved in x/y directions, NOT that the sensor is restricted to solely moved in x and y directions only which is just useless and impractical for an anti-shake system like this. There is rotational correction of the Minolta/Sony AS system and its DOF is 3, and in 2D. The key to achieve this is that there are two y-axis sliders and one x-axis one, which essentially makes any rotational movement possible.

Still believing that products are not made based on patents? I don't believe it! You can say that they are not identical, but saying that patent is not used in the final product is just somehow unrealistic, I am afraid to say.
Please help me here and point me to the text passage that confirms 3 degrees of freedom. I did not find it, and therefore don't believe it. Quite the contrary, I found claims by other people in different forums that the Pentax SR system is the only one in the market with rotational correction.

...however, to strike my original point, we seem to agree that Canon, Nikon and Olympus will not be able to offer Astrotracing without a massive overhaul of their image stabilization technology. Since that overhaul is unlikely, we have: Pentax leading the industry, and that will stay for some time. Which was my point.
Okay, Chris, I've re-read in more details for your provided Sony marketing page and info and I am standing corrected.

It is surprised to learn and see that the Sony sensor-shifted stabilisation system actually has only two degrees of freedom, against what was designed in the original Minolta AS patent, which clearly has all the three degrees of freedom.

The implementation is simplified after all. But in practice, how come they did not include / rule out the "Roll", which is somehow impractical as I said last time.

P.S. With the in-depth knowledge about the SR system as well as the real user experience with the O-GPS1 of yours, I am eager to see a full review of it by you, preferably with some photos produced by the combo. Willing to write and share with us at the Pentax Fans Club Blog very soon, Chris?
Rice -
you gotta be kidding. I have provided the skeleton of an article up there. I am willing to put more "butter to the fish", as we say in Germany, as soon as I can, but I am not a blogger but a reader, I am not a fanboy but a satisfied customer, and the whole point of me writing in your blog is to try and balance your rants about Pentax here.
So wait until I've taken some more pictures using the O-GPS1, and I will be happy to post some more here. Until then, the stuff above is already something to discuss. (but apparently, it seems that in the meantime everybody else has left this site...)
Chris
I am serious. If you have really good experience about an unique product which you are totally satisfied with, why not show the results to us? Would you mind?
I do not claim that patents are never used in a product (it would be obvious nonsense to say that). I say that if you want to compare products, compare products. Patents may give you hints, but in most cases, they do not describe actual products but rather ideas which might be used in full, might be used in part, or might not be used at all. Heck, the product can even have many features MORE than the patent, and you know why. So while your strategy of comparing the patents of different companies is a nice idea, you will make mistakes if you draw DIRECT conclusions to the products of those companies.

E.g., to my knowledge the SR mechanism of K-r (or was it K-x, I am always confused by the mid-range product names) and K-5 are different.

Post a new comment

Comments by