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Forum: General Photography 10-13-2017, 12:05 AM  
Does IBIS affect precise focusing and exposure metering?
Posted By Fogel70
Replies: 44
Views: 1,951
I believe the guy tries to explain the distinction between continuous AF and tracking AF.

Continuous AF tries to keep focus on the the the selected point(s) without any further function trying to keep track of the object in focus. With continuous AF it up to the photographer to track the subject.
While tracking AF use more information of the subject to keep tracking it. FI trying to calculate the size of the subject, the motion of the subject in the VF and maybe even the color of the subject.

Mirrorless cameras may have even more advanced functions for tracking. FI tracking eyes of an model.
Forum: General Photography 10-11-2017, 09:00 AM  
Does IBIS affect precise focusing and exposure metering?
Posted By Fogel70
Replies: 44
Views: 1,951
I don't have much experience with canon, but with single point AF the focus can easily jump onto something that comes in front of the subject you try to track. So with single point AF you have continuous AF, but no real tracking of the subject.
Understanding Canon 5D Mark IV Autofocus - AF Points & AF Areas
Forum: General Photography 10-10-2017, 08:35 PM  
Does IBIS affect precise focusing and exposure metering?
Posted By Fogel70
Replies: 44
Views: 1,951
Setting the camera for single AF point and spot metering for this type of shot, seems more like an user error than a limitation of the system. Single AF point is designed for AF-S and AF tracking do not work properly with it selected, even on cameras with optical stabilization. AF tracking need input from several AF point to be fully functional.
Forum: Pentax SLR Lens Discussion 10-09-2017, 05:36 AM  
HD lens coating -- bad name?
Posted By Fogel70
Replies: 27
Views: 909
Don't forget that they also have Aero Bright and SP coatings.
So maybe it's time to add them all together in an SPABHD coating, or Super Protect Aero Bright High Density coating.
Forum: Pentax DSLR Discussion 09-29-2017, 02:02 AM  
Is the moving sensor slowing autofocus????
Posted By Fogel70
Replies: 91
Views: 3,136

There are basically 4 different types of corrections done for image stabilization in cameras and lenses.

Number of axis and what type of motion each type compensate for.
2-axis : Yaw + pitch (first generation of sensor stabilization and in most stabilized lenses)
3-axis : Yaw + pitch + roll (second generation of sensor stabilization) In most Pentax DSLRs before K-1.
4-axis : Yaw + pitch + up/down + left/light (used in some macro lenses)
5-axis : Yaw + pitch + roll + up/down + left/right (third generation of sensor stabilization) On Pentax K-1 and later

The sensor itself has 3 motions: Roll + up/down + left/right, but has a motion sensor for each axis of motion it can compensate for.
Angular velocity sensors for yaw, pitch and roll, and accelerometers for up/down and left/right motion.

Yaw and pitch is corrected by up/down and left/right motion of the sensor.
Forum: Pentax DSLR Discussion 09-28-2017, 05:56 AM  
Is the moving sensor slowing autofocus????
Posted By Fogel70
Replies: 91
Views: 3,136
Below is what Ricoh says.


The PENTAX-original sensor-shift-type shake reduction mechanism has been upgraded to provide optimum compensation for all lenses used in handheld shooting. The new-generation SR II (Shake Reduction II) features a five-axis mechanism to compensate for camera shake caused by horizontal and vertical shift** (often generated in macro photography) and camera shake caused by roll, which is difficult to handle by lens-installed shake reduction mechanisms, in addition to more common camera shake caused by pitch and yaw. The SR II unit is controlled with great precision as soon as the camera’s power is turned on, and provides a wide compensation range — as much as five shutter steps*** — to expand the limits of handheld shooting.

Forum: Pentax DSLR Discussion 09-27-2017, 08:16 PM  
Is the moving sensor slowing autofocus????
Posted By Fogel70
Replies: 91
Views: 3,136
Yes, when shooting macro it's the lateral shake that dominates. Yaw and pitch shake is the same independent of maginification of the shot.
So for macro it's mainly the two extra lateral axis of compensation in 5-axis stabilisation that helps.
Forum: Pentax DSLR Discussion 09-15-2017, 01:57 AM  
Poll: What is the most important feature in a camera?
Posted By Fogel70
Replies: 49
Views: 1,638
To me it's the whole package that are most important.
It not the 99 great features that matters most, it the 1 bad feature that going to make the difference.

The weakest link need to be as strong as possible.
Forum: Pentax K-3 07-28-2017, 05:02 AM  
Weather resistance is a fake?
Posted By Fogel70
Replies: 104
Views: 5,702
DSLR can't get weather sealed rating by JIS and / or IP standards as the mount is not sealed against water entering. The same for lenses.
So even if the DSLR used with a lens is sealed well enough to requirements of the JIS and / or IP standards, the DSLR or the lens themselves can't get approved for JIS and / or IP certifications. Or at least not a rating high enough to be worth to mentioned by the manufacturer. If the lens was fixed on the camera I'm pretty sure Pentax would fulfill JIS and / or IP standards high enough to be mentioned on the datasheet.

A weather sealed Pentax DSLR would probably get a IP rating of IP10 and a weather sealed Pentax lens IP20.
And if above DSLR and lens were fixed together they would probably get get rating of IP52 or IP62.

Because none of the DSLR or lens is fully sealed, it will be difficult claim warranty on damages caused by water.
The damage could be caused by the user not being careful enough. FI a grain of sand on the lens o-ring could be enough to cause a leakage between lens and camera.

IP Rating Chart |
Forum: Photographic Technique 07-18-2017, 08:03 AM  
Can I lock the AE in MF mode in Manual?
Posted By Fogel70
Replies: 6
Views: 699
The EV-scale in manual mode show how much your exposure settings differs from what the camera think is "correct" exposure. If you are using spot metering in manual mode and want to use the exposure value the camera suggest, you have to manually dial in the exposure until the EV-scale is centered. There is no point in using Auto Exposure-lock in manual mode as there is no "Auto Exposure" to lock.

You can also use green button for metering in manual mode (if your camera has green button) as green button turn on auto exposure in manual mode. By default green button is set to P-priority, but can be changed to Shutter- or Aperture-priority in custom settings. This works similar to using AE-lock in auto exposure modes, but with the advantage of not changing exposure until you press the green button again. Which is a reason why I prefer M-mode for spot metering.
Forum: General Photography 04-04-2017, 05:57 AM  
Why do filters attach to the front of lenses and not the rear?
Posted By Fogel70
Replies: 25
Views: 1,008
You can't move the lens further out from the camera without changing the lens ability focus.

The optics in a teleconverter simply compensate to keep focus on infinity while moving the lens further out from the camera. It's not possible to do this without adding "teleconverter properties".
Removing the "teleconverter properties" will make the lens loose ability to focus on infinity, but gain ability to focus closer.
Forum: Pentax DSLR Discussion 03-21-2017, 07:35 AM  
Fastest M-Mode ever... if the Green Button was implemented consistently -.-
Posted By Fogel70
Replies: 19
Views: 1,008
Another way for this would be an option to turn off the automatic metering in any mode.
It could maybe be called "reversed AE-lock" as an option for AE-lock button, where exposure is locked except when AE-lock button is pressed.

Because what you want is basically the Hyper-P mode (and TAv-mode) with the automated metering turned off, and replaced by a metering only done by press of a button.
Forum: Pentax DSLR Discussion 03-21-2017, 06:32 AM  
Fastest M-Mode ever... if the Green Button was implemented consistently -.-
Posted By Fogel70
Replies: 19
Views: 1,008
They could add an "auto" option to the green button for manual mode so it keep the setting changed last.

But in most cases I prefer to be able to select which parameter it always should change. In 95% of the cases I want to only change shutter speed independent of which parameter I changed last.
I may fine tune shutter speed after I press green button to set shutter speed, but next time I press green button I still want it to set the shutter speed.
Forum: Troubleshooting and Beginner Help 03-20-2017, 03:43 AM  
K70 issue for a first time Pentax user
Posted By Fogel70
Replies: 7
Views: 722
In live view the shutter has to close before the image is captured, and then open again after the picture is captured to go back in LV mode.
So it close the shutter before the image is captured, open shutter to start capture the shot, and close the shutter to end the capture, then open shutter again to enter live view mode after the image is captured.
I'm not sure how K70 shutter/mirror mechanism is designed. but it may be that the mirror also have to close every time the shutter close.
Forum: Pentax News and Rumors 02-07-2017, 07:19 AM  
Thom expects a new Pentax camera
Posted By Fogel70
Replies: 294
Views: 19,150
Maybe it's a 720 degree Theta.
Forum: Pentax KP 01-27-2017, 05:49 AM  
SR Unavailable in Live View???
Posted By Fogel70
Replies: 13
Views: 883
It's probably something lost in translation.
Maybe it's the same old "SR not available when using self timer" that they refer to.
Forum: Pentax News and Rumors 01-19-2017, 04:15 AM  
rumored Pentax mirrorless camera - something between K1000 and K-01
Posted By Fogel70
Replies: 480
Views: 40,215
I believe M-mount is too narrow to work well with electrical contacts. And it might be difficult to add contacts and still keep it fully compatible with existing M-mount lenses. Many of the M-mount lenses protrude quite far inside the mount so the electrical contact would have to be positioned deep inside the camera which would make a weird design, and it would limit the optical design.
Another issue is the longer register distance of M-mount would limit support from third party lens manufacturers. They would not be able to use existing mirrorless lens designs for Pentax mirrorless.

Not even Leica choose to keep the M-mount for modern mirrorless system. Leicas L-mount would be a better solution for autofocus mirrorless.
Forum: Troubleshooting and Beginner Help 12-27-2016, 07:45 AM  
k-70: Viewfinder exposure bar instead a tilt measurement
Posted By Fogel70
Replies: 4
Views: 617
It's not much point of showing exposure bar in any (semi) automatic mode, as the point of the automation is to keep the exposure in the center of the exposure bar.
But if you add exposure compensation in a (semi) automatic mode, I believe you will see the exposure bar.
Forum: Pentax Medium Format 11-30-2016, 03:10 AM  
Can next 645 digital be made less deep?
Posted By Fogel70
Replies: 20
Views: 1,917
It would also need a redesign of the optics of the OVF.

Here you can see how 645Z looks inside.
Pentax 645Z Cut in Half - CP+ 2015 |
Forum: Pentax K-1 11-26-2016, 02:10 PM  
K-1 Program Line
Posted By Fogel70
Replies: 1
Views: 717
In auto I believe it can switch between any of the other available PL, but normal is a fixed setting that always use a fixed PL curve.
Normal will use the same logic as if using a non-program mode.

In most cases auto PL will probably choose normal PL, so you might not notice much difference.
Forum: General Photography 11-26-2016, 11:02 AM  
what makes Pentax ppl so defensive?
Posted By Fogel70
Replies: 121
Views: 4,693
It's probably easy to explain. Pentax user base is probably one of the oldest, and most experienced.
And if you choose to be a Pentaxian you have most likely spent quite some time on investigating on which brand that give you what you need, and will feel more secure in your choice.

So I would say that Pentax users are older, more experienced and have more knowledge on photography in general.
Which tend to make people more open minded.
Forum: Troubleshooting and Beginner Help 10-27-2016, 01:16 AM  
Focal Length
Posted By Fogel70
Replies: 7
Views: 666
Pentax used to show focal length of the back LCD on older cameras, but they have stopped this since some years.
Now you have to look at the lens.
Forum: Pentax DSLR Discussion 10-24-2016, 07:36 AM  
About IBIS - Which company started IBIS in DSLR's ? Curiosity question.
Posted By Fogel70
Replies: 27
Views: 2,034
Who would not want one of these? :D
Pentax - Magnum Explorer
Pentax - Rampage Tornado
Pentax - Firebird Interceptor
Pentax - Spitfire Javelin
Forum: Pentax News and Rumors 10-22-2016, 02:43 PM  
HD PENTAX-DA 55-300mmF4.5-6.3ED PLM WR RE
Posted By Fogel70
Replies: 659
Views: 64,720
One issue with a dual design like this is that it adds complexity to all steps from R&D to production.

- It require more resources on design and evaluation for R&D. And trying something new, never tried before, makes it difficult to know how much evaluation is needed.
- The extra cost of the dual AF might mean that the the budget for the AF-motor where lower that if the lens had AF-motor only. Which could make it more difficult for sourcing to find a suitable motor.
- The extra complexity in production add cost to the lens, cost for the extra parts, extra parts to assemble, extra QC. Cost that might have to be saved somewhere else in the process.

I haven't heard any problems on the AF-motor used in the Tokina version of the lenses. If Tokina and Pentax had not used different AF solutions, they could have co-developed it instead.
Forum: Pentax DSLR Discussion 10-22-2016, 12:39 PM  
About IBIS - Which company started IBIS in DSLR's ? Curiosity question.
Posted By Fogel70
Replies: 27
Views: 2,034
Pentax was alone for some years in using electromagnets for IBIS though (by now everyone seems to gone over to similar designs).
This makes it possible to move the sensor more freely, and easier to implement many other functions that moves the sensor.
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