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Forum: Pentax Camera and Field Accessories 11-22-2018, 02:18 PM  
Supporting a D FA 150-450mm lens: Use existing Arca-Swiss ball head or get a gimbal?
Posted By bwDraco
Replies: 13
Views: 690
Hmm... While I haven't had issues with using the ball head the "normal" way with my 70-200 (again, the Arca-Swiss Monoball uses an aspherical ball that is more resistant to tipping over than conventional ball heads), I'll be sure to give this technique a shot. Thanks for the hint 🙂

Draco

---------- Post added 11-22-18 at 04:44 PM ----------

You mean like this?



I tried doing this briefly and I didn't quite like it. Also, there's metal-on-metal contact where the stem beneath the clamp comes into contact with the drop notch and that would wear it down very quickly.

Draco
Forum: Pentax Camera and Field Accessories 11-22-2018, 12:03 PM  
Supporting a D FA 150-450mm lens: Use existing Arca-Swiss ball head or get a gimbal?
Posted By bwDraco
Replies: 13
Views: 690
Thanks for the advice. I'll probably just get the lens and plate, and add accessories as needed.

As for the gimbal, the GH-30 looks really nice for the money. I'd suppose it's just a small step down from the WH-200 in terms of build quality.

I have no reason to doubt the integrity of my Arca-Swiss head (it's designed to cope with upwards of 100 lbs of weight), but what's your experience with using a ball head with a large lens? The 150-450 is a bit larger than Canon's 100-400 II, and I'm seeing people use both ball heads and gimbal heads with the latter.

Draco
Forum: Pentax Camera and Field Accessories 11-22-2018, 11:40 AM  
Supporting a D FA 150-450mm lens: Use existing Arca-Swiss ball head or get a gimbal?
Posted By bwDraco
Replies: 13
Views: 690
So... I'm looking to get a Pentax D FA 150-450mm lens (and a Wimberley P-40 QR plate to go with it) within the next few months (funding permitting), and I'm wondering if I can get by with my existing Arca-Swiss Monoball Z1+ sp or if I should get a gimbal head:
  • The Arca-Swiss Monoball heads are better-behaved than most ball heads with heavy lenses due to their aspherical ball making them less likely to tip over with a very heavy load. But I'm getting the feeling that a gimbal is still a better option. Is the 150-450 large or heavy enough to justify getting a gimbal?

  • An intermediate option is the Wimberley Sidekick, a gimbal attachment for ball heads. However, Wimberley states that they do not recommend using the Arca-Swiss double-decker clamp (which is what my Monoball Z1+ sp has). What potential issues might arise with this arrangement?

  • A standalone gimbal head is generally considered the best option; however, it's expensive and quite bulky. The Manfrotto 393 isn't an ideal substitute because it uses a proprietary QR system which is not Arca-Swiss-compatible. Is a Wimberley WH-200 worth it?

In all cases, the camera, lens, and head will be placed on a Manfrotto MT055CXPRO3 tripod (carbon fiber, 9 kg/19.8 lb capacity).

Your thoughts?

Draco
Forum: Pentax K-3 11-20-2018, 11:57 AM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
The edges did improve.

Sadly, I am past the 90-day repair warranty period. I may have to pay for a second repair. I'll see what I can do about this.

Draco
Forum: Pentax K-3 11-19-2018, 11:26 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
Okay guys, sorry for the late reply... The camera came back with the mirror cleaned. Precision said that they did not find any delamination.

However, I am seeing faint bubbles of the same kind appear again gradually upon close inspection. The pattern of bubbles is the same as before, which would indicate delamination.

Any ideas?

Draco
Forum: Pentax Camera and Field Accessories 11-07-2018, 04:54 PM  
Just bought into the Arca-Swiss QR system
Posted By bwDraco
Replies: 7
Views: 813
So... I've posted an image of the Mandarin Duck on my Instagram account.

It hasn't gone through my full post-processing routine; I had only processed the RAW on my phone quickly using Snapseed. Regardless, I almost cried when I saw it and had to work my way through a big crowd in order to even get in position and set up my tripod.

Draco
Forum: Pentax Camera and Field Accessories 11-03-2018, 07:28 AM  
Just bought into the Arca-Swiss QR system
Posted By bwDraco
Replies: 7
Views: 813
Surprise: I actually got a Manfrotto MT055CXPRO3 for my birthday coming up soon. I'm bringing it to Central Park today along with the Monoball Z1+ sp to see if I can capture that elusive Mandarin Duck that's been making the rounds on social media...

Draco
Forum: Pentax Camera and Field Accessories 10-23-2018, 04:17 PM  
Just bought into the Arca-Swiss QR system
Posted By bwDraco
Replies: 7
Views: 813
Arca-Swiss heads have a few different Quickset options, including a twist lock and a lever lock. The lever lock is not guaranteed to be compatible with anything other than Arca-Swiss's own plates because it's designed to open and close to specific widths, and plates with different widths will not fit correctly. The twist lock does not suffer from that problem because it's continuously variable, but it's also slower to operate.

I have the twist-lock version of the Monoball Z1+ sp and haven't had any issues with the third-party (SpiderPro) plate thus far. I also have a genuine Arca-Swiss 40mm universal-fit plate; though I haven't tried it, I have no reason to believe that there would be any issues.

Draco
Forum: Pentax Camera and Field Accessories 10-23-2018, 09:00 AM  
Just bought into the Arca-Swiss QR system
Posted By bwDraco
Replies: 7
Views: 813
After over a year of being on the fence, I've finally bought into the Arca-Swiss quick-release system. I've acquired an Arca-Swiss Monoball Z1+ sp and a couple of plates, including a SpiderPro lens collar plate for use on my D FA* 70-200mm lens. I'm using this on my Oben CTM-2500 monopod, but will eventually get a better monopod as well as a proper tripod, (edit: see post #6) not to mention more lenses. Alas, my budget is limited and I don't have that much money to acquire all that gear at once.

The free motion allowed by a ball head takes some time to get used to, but the advantage of the Arca-Swiss head is that doesn't tip over as easily under load because it uses a spheroid ball whose tension increases as you move it away from the center position, addressing a problem I've constantly had with the tilt head it replaced.

The hard part, however, is properly deciding what heads and plates to buy. The Arca-Swiss QR system is very confusing to a newcomer, and I talked with the B&H sales associate for a long time before buying, discussing how supposedly "Arca-compatible" plates and mounts can be incompatible with other manufacturer's due to proprietary extensions and modifications, such as pins or other protrusions in the head and/or plate and inconsistent plate widths.

One last thing: B&H only lists the Monoball Z1 sp but the new Z1+ sp has the same SKU, so don't be alarmed if you can't find the new Z1+ model on their website.

Any hints on using this or suggestions on future expansion? Your thoughts on the Arca-Swiss system and its compatibility issues?

Draco
Forum: Pentax K-3 08-16-2018, 04:15 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
It's been sent to Precision for repair. I've made it very clear on the letter inside the package that the AF sub-mirror is delaminating and must be replaced, not merely cleaned.

The camera is out of warranty. My first job of the next season is September 1, so I'm paying for an expedited repair. Furthermore, I've shipped it out via Priority Mail Express for guaranteed overnight delivery, something I don't usually do.

Draco
Forum: Pentax K-3 08-15-2018, 07:50 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
Late reply, but I have inspected the AF sub-mirror again and the spots have reappeared, exactly where they were before I tried to "clean" them". The camera has seen very little use over the last few months. At this point, I am absolutely convinced that this is delamination and not contamination.

Ricoh seriously needs to know about this.

Draco
Forum: Product Suggestions and Feedback 06-17-2018, 11:11 AM  
Mirror cling clang when play, or enter the menu from live view
Posted By bwDraco
Replies: 3
Views: 809
The problem is that it takes energy to keep the shutter open and the sensor active. (On the K-3 family, as far as I can tell, keeping the mirror up alone does not require extra energy.) As such, the camera simply closes the shutter and lowers the mirror when in the menus. This behavior is by design, but at least the K-3 would automatically resume live view when you exit the menu. (The K-5 did not and you had to press the live view button again to do the same.)

Draco
Forum: Pentax K-3 05-22-2018, 10:59 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
Bubbles could just be voids between the surface and substrate. I can't really tell the difference between contamination and delamination at this point.

Draco
Forum: Pentax K-3 05-22-2018, 07:35 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
Now this is interesting. I put a cotton swab on it and the spots disappear. However, merely putting pressure on the mirror is enough to remove the spot, and I see no indication of streaking when I gently wipe it.

Hence, this does not rule out delamination as pressure can cause sub-surface bubbles to disappear, but it does suggest it could just be oil or other contamination.

Autofocus consistency has improved dramatically since this operation. I'll be monitoring this closely to see if this issue reappears.

Draco
Forum: Pentax K-3 05-21-2018, 02:53 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
Possibly. As far as I can tell, Precision only performed a CLA on the camera and its AF system; the AF sub-mirror may not have deteriorated to that point or they may not have recognized the true nature of the problem. The inconsistency reappeared a few months after the service.

Draco
Forum: Pentax K-3 05-21-2018, 12:45 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
The sensor was last wet-cleaned more than a year ago, and I have never cleaned the mirror with anything other than a blower bulb.

Liquid ingress seems possible, but that wouldn't really explain the spots in the middle of the AF sub-mirror, and the main mirror shows no evidence of similar contamination or damage.

Draco

---------- Post added 05-21-18 at 04:19 PM ----------

On my K-5, it looks like this:



Most of the spots in this case are dust, but notice the same discoloration around the edges.

Draco
Forum: Pentax K-3 05-21-2018, 11:04 AM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
I think I did post photos. Are you able to access Imgur?

Draco
Forum: Pentax K-3 05-21-2018, 08:22 AM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
On my camera, some of the spots bleed into the edge, so I'm pretty sure it's delamination.

I suspect the OP of that post merely pushed out the bubbles during "cleaning".



Draco
Forum: Pentax K-3 05-20-2018, 11:03 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
Found this thread reporting the same issue: autofocus inaccuracy, green spots on the mirror? - PentaxForums.com

If anyone else has autofocus sub-mirror delamination, please tell us about it. We might have a serious design flaw on our hands.

Draco

---------- Post added 05-21-18 at 02:07 AM ----------

Another thread reporting this problem: pentax mirror spots - PentaxForums.com
Forum: Pentax K-3 05-20-2018, 09:26 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
I took a closer look at my old K-5 and I found similar delamination of the AF sub-mirror. This points to a design flaw that Ricoh may not be aware of and needs further investigation.

Everyone, try gently lifting up the reflex mirror on your camera(s) slightly and examine the small mirror beneath it for delamination. Be careful not to touch the surface of the mirror; touch only the lower edge and consider using gloves. We need to find out if there's a hitherto unnoticed design flaw in the mirror assembly and if so, tell Ricoh about it.

I just sent a Tweet to Ricoh Imaging US regarding AF sub-mirror delamination; hopefully, this will get more attention about this problem.

Draco
Forum: Pentax K-3 05-20-2018, 08:41 PM  
AF sub-mirror delamination causing inconsistent focusing anyone else affected?
Posted By bwDraco
Replies: 50
Views: 4,607
My Pentax K-3 II has been suffering from occasional focusing problems where the camera may lock focus far off target at times even in good light on a high-contrast subject. The error is typically front-focus but can sometimes be back-focus, and cannot be addressed by AF fine adjustment because of its inconsistent nature. The behavior also appears to be somewhat dependent on color temperature. All of my lenses are affected.

I tried cleaning the AF sensor with a blower bulb and while it appears to have improved, it did not completely address the problem. Should I try again, or send in the camera?

Has anyone else sent in their cameras to Precision for this issue, and did they address it effectively? If I'm to send mine in, should I send in the lenses as well? The camera is out of warranty, but that's not an issue for me.

Draco


It turns out the problem is delamination of the AF sub-mirror. How this is even possible is beyond me, but it looks like this will have to be sent to Precision.




Anyone else experienced this issue? Here's the note I'd send with the camera:


Draco
Forum: Visitors' Center 04-23-2018, 08:16 PM  
Pentax K-3 II with weather proof-sealed body
Posted By bwDraco
Replies: 19
Views: 1,921
The K-3 II is technically discontinued but remains available from major dealers, including B&H and Adorama. While it is highly resistant to water and dust ingress, it is not completely impervious to the elements. I've personally dealt with a malfunction on my K-3 II (with no lasting damage) after continuous exposure to heavy rain for more than an hour during a soccer assignment more than two years ago.

Draco
Forum: Pentax Full Frame 02-22-2018, 02:59 AM  
K-1 Mark II: Accelerator unit frees up processing power for autofocus?
Posted By bwDraco
Replies: 31
Views: 3,869
@MJKoski, this isn't medium format we're talking about. Although it's best for landscape and studio photography, the K-1 Mark II is meant to be a multipurpose camera that can handle a bit of action as well.

Draco

---------- Post added 02-22-18 at 05:08 AM ----------



Per Ricoh Imaging, the accelerator unit performs image processing before the data gets to the main PRIME IV engine:

Draco
Forum: Pentax Full Frame 02-22-2018, 01:26 AM  
K-1 Mark II: Accelerator unit frees up processing power for autofocus?
Posted By bwDraco
Replies: 31
Views: 3,869
The idea I had in mind was the image processing requires a certain amount of processor resources. For predictable performance, specific amounts of processing power are reserved for this purpose. Because this is now done by a separate accelerator unit, fewer resources can be reserved for image processing and noise reduction, which means that the AF system can use more of the processor than before. Is this technically possible?

Draco
Forum: Pentax Full Frame 02-21-2018, 11:02 PM  
K-1 Mark II: Accelerator unit frees up processing power for autofocus?
Posted By bwDraco
Replies: 31
Views: 3,869
An interesting idea came up while I was thinking about the changes in the K-1 Mark II.

The press release states that the noise reduction is handled by the accelerator unit first seen in the K-70. This enables a significant improvement in noise handling under extreme low-light conditions. It also states that the K-1 Mark II has updated AF algorithms.

However, most of the hardware is exactly the same. The continuous shooting speed is still only 4.4 fps in full-frame mode, which AFAICT is limited by the image sensor's readout speed and not the processor. But why can't the old K-1 get the same AF improvements?

It dawned upon me that by offloading image processing, including noise reduction, to the accelerator unit, more processing power is available for the autofocus system. This enables the use of more complex predictive tracking algorithms, which would result in enhanced AF performance.

Any official word on this?

Draco
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