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Forum: Pentax Medium Format 07-03-2019, 11:10 AM  
Help + Advice: Pentax 67 Light Leak Or?
Posted By glass
Replies: 8
Views: 617
Apologies this is a little off topic and I have nothing constructive to add, but I love that first picture. Sorry it got ruined. What lens did you use to capture that?
Forum: Pentax Medium Format 12-01-2018, 04:17 PM  
Pentax 67 TTL Prism - cannot remove diopter eyepiece
Posted By glass
Replies: 3
Views: 707
I have the Pentax TTL prism viewfinder.

I cannot turn the knurled ring that holds the diopter eyepiece in place. I understand from the manual that it is supposed to unscrew anti-clockwise, but mine is stuck fast. Any tips on how to remove this? Thanks.
Forum: Pentax Medium Format 06-10-2018, 01:56 PM  
Pentax 67 150mm f/2.8 - Additional aperture stop
Posted By glass
Replies: 4
Views: 785
Ahh, that makes sense. Thank you both.
Forum: Pentax Medium Format 06-10-2018, 07:29 AM  
Pentax 67 150mm f/2.8 - Additional aperture stop
Posted By glass
Replies: 4
Views: 785
I have the Pentax 67 150mm f/2.8. The f/2.8 setting is marked with a dot, but this is the 2nd click on the aperture ring. If I select the 1st click (wide open, f/2 position) the picture is very soft.

I can't find a manual for this lens. What is the additional click past f/2.8 for?

Thanks.
Forum: Pentax Medium Format 03-28-2017, 01:21 PM  
Fuji GFX useage compared to 645Z
Posted By glass
Replies: 48
Views: 7,418
The biggest problem I have with the 645z is to do with live view magnification for critical focusing. On the 645z, it takes an age to move the square around the screen and zoom in. The User Interface operation changes between manual focus and auto focus modes, which is a problem on a lens like the 45mm. The ergonimics of the Fuji in this regard are very good - the whole system is designed around live view focusing and it is so fast to move around the screen and select 100% view, either on the rear display or the EVF.
Forum: Pentax Medium Format 02-07-2017, 01:10 PM  
645z Wireless Transfer to Ipad?
Posted By glass
Replies: 7
Views: 1,239
I confirm the Eye-Fi card works really well in my 645z, including the in-camera menu option to enable or disable wi-fi transfer. So I guess it is a defective card you have.
Forum: Pentax Medium Format 10-16-2016, 01:12 AM  
WTB 67 105/2.4 Lens. What Adaptor Do I need for 645Z
Posted By glass
Replies: 13
Views: 1,239
When I was looking, I found the best price in the UK for a new adapter was on Amazon https://www.amazon.co.uk/Fotodiox-Mount-Adapter-Pentax-Camera/dp/B0054EP3EA/...d817dda071c43c - about the same price as used ones on eBay, and cheaper than the used Pentax ones.
Forum: Pentax Medium Format 10-07-2016, 11:31 AM  
Which a Better Walk around Lens..645 FA 55 or 645 FA 75
Posted By glass
Replies: 11
Views: 1,249
The 75 has become my always-have-with-me lens. The 55 is optional for me, as sometimes I prefer 45 or 35. Going the other way, sometimes I prefer 90 or 105. But I always seem to find 75 is just right. And it is really small, which is a plus.
Forum: Pentax Medium Format 06-19-2016, 05:13 AM  
First day with 645
Posted By glass
Replies: 8
Views: 1,198
That is right, it isn't the heat :) A larger sensor means the angle of view for a given focal length is larger. So your 80mm of medium format will be much wider than 80mm on Full Frame, and much wider again than 80mm on APS-C.
Forum: Pentax Medium Format 06-09-2016, 01:28 PM  
SMC Pentax 67 f/2.8 - Jagged aperture blades?
Posted By glass
Replies: 7
Views: 868
Great, thanks. Wonder why they designed it like that? 10 aperture blades is an unusual number as well, I wonder if there is an optical reason for this.
Forum: Pentax Medium Format 06-09-2016, 02:00 AM  
Help required for Focus Issue
Posted By glass
Replies: 5
Views: 769
Same here, back button AF, disabled on the shutter, 55mm f/2.8. It focuses faster and more accurately than my Canon 5D II ever did. I don't expect it to be as fast as a 7D II or 5D III though.
Forum: Pentax Medium Format 06-09-2016, 01:46 AM  
SMC Pentax 67 f/2.8 - Jagged aperture blades?
Posted By glass
Replies: 7
Views: 868
Doh! 165mm f/2.8.
Forum: Pentax Medium Format 06-08-2016, 04:32 PM  
SMC Pentax 67 f/2.8 - Jagged aperture blades?
Posted By glass
Replies: 7
Views: 868
If anybody has this lens, please would you check if the aperture blades form a sawtooth or jagged pattern as you stop down from f/2.8 to f/8? At f/8, the aperture blades form a normal shape without jaggies.

From f/8 to f/22, one of the blades seems shorter than the others, giving a non-perfect 'circle' that is lopsided.

Thanks.

This is the 165mm f/2.8
Forum: Pentax Medium Format 05-28-2016, 04:44 PM  
Pentax 645Z for lowlight shooting?
Posted By glass
Replies: 24
Views: 5,123
With a slower shutter, I think the flames and sparks would look different.
Forum: Pentax Medium Format 05-20-2016, 11:56 AM  
Pentax 67 165mm Leaf Shutter doesn't always fire in Auto Aperture
Posted By glass
Replies: 19
Views: 2,292
Thanks, hadn't seen the manual before.

I confirm with the modification, lenses work with both Pocketwizards and Profoto remote triggers.
Forum: Pentax Medium Format 05-20-2016, 08:26 AM  
Pentax 67 165mm Leaf Shutter doesn't always fire in Auto Aperture
Posted By glass
Replies: 19
Views: 2,292
:o



I didn't realise this was the official line. Where is this documented?
Forum: Pentax Medium Format 05-20-2016, 04:55 AM  
Leaf shutter "look"
Posted By glass
Replies: 8
Views: 2,496
Thanks for all your responses. I did some testing and there is a distinct difference in bokeh between LS and FP. As mentioned above, this is most noticeable at 1/500 wide open, and the effect diminishes at slower speeds and at smaller apertures. The LS bokeh is so much smoother, almost more like a gaussian blur effect, whereas the FP bokeh is more choppy with 'doubling' of visible elements, especially straight lines. This makes the objects in the LS bokeh remain intelligible, whereas the FP blur can be quite confusing to make out what the objects are.

The sharpness difference is down to camera movement. Without paying careful attention to technique (e.g. heavy weighted tripod and mirror lock-up), many FP shots have a tiny amount of motion blur (even at 1/500) whereas almost all of my LS shots are tack sharp, even hand held at 1/500. As my shooting technique is the same between LS and FP, I guess the extra blur is due to mirror slap.
Forum: Pentax Medium Format 05-20-2016, 04:42 AM  
Pentax 67 165mm Leaf Shutter doesn't always fire in Auto Aperture
Posted By glass
Replies: 19
Views: 2,292
I should have added that this problem only occurs on a 645z. I'm pleased to announce I've found a solution to this problem.

I purchased a number of 67 LS lenses as at first I thought it was a problem with my particular lens. But on my 645z they all exhibited problems with the LS not firing reliably.

It turns out that the aperture tab on the back of the lens mount needs to fall back to the home position exactly, or the leaf shutter mechanism won't completely reset. The 67 to 645 adapter has a hard stop which prevents the lens' tab from completely returning far enough to the home position. For aperture control only, this is no problem as this would simply cause the aperture to be ever so slightly closed instead of wide open, but not enough to be noticeable. But it does cause a problem with the Leaf Shutter mechanism; without returning to the full open position it causes the Leaf Shutter to fail on the next shot.

I tried multiple 67 to 645 adapters, including genuine Pentax and Fotodiox, and had the same problem on all.

The solution was to file away part of the metal hard return stop on a Fotodiox adatper, allowing the lens' aperture tab to completely return to the correct home position. Now all my 67 LS lenses fire accurately, 100% of the time. Very happy with this and hope it helps other users with a similar problem. The 67 LS lenses on a 645z are very beautiful.

The other benefit of 67 LS lenses vs the 645 LS lenses is the 67 lenses have auto aperture, the 645 lenses are stop-down only.
Forum: Troubleshooting and Beginner Help 05-11-2016, 02:32 PM  
645D + SMC 645 LS 75mm F2.8
Posted By glass
Replies: 6
Views: 1,107
If the lens is set to O mode, you set shutter speed on the camera normally, so 1/8sec is not required (unless that happens to be the exposure you actually want). But with those settings you shouldn't get a black picture.

If you take the lens off the camera, cock the leaf shutter, then look through the lens while you press the small aperture lever on the back of the lens mount (the one that you can press to make sure the aperture is working), what happens when you look through the lens? Set at f/2.8 and O mode, nothing should happen.

What happens if you put the lens back on the camera, cock the shutter in O mode, then look through the viewfinder and select depth of view preview. Does the viewfinder go black? It should stay clear.
Forum: Troubleshooting and Beginner Help 05-11-2016, 11:54 AM  
645D + SMC 645 LS 75mm F2.8
Posted By glass
Replies: 6
Views: 1,107
Before you take the picture, can you see through the viewfinder, or is it black?
What about after you've taken the picture - is the viewfinder visible or black?
What aperture and shutter speed are recorded in the EXIF of the black frame photo?
Forum: Pentax Medium Format 05-10-2016, 10:35 AM  
Leaf shutter "look"
Posted By glass
Replies: 8
Views: 2,496
I've been experimenting with my new eBay acquisitions and I get a feeling that when I shoot using the leaf shutter, the photos look different to when I use the Focal Plane shutter. I can't identify what is different, perhaps a bit sharper, a bit more contrastier, slightly different bokeh?

Are there any proven physics behind a leaf shutter rendering slightly differently to a focal plane shutter? Or is there such a thing as a 'leaf shutter look' (in a similar fashon to a 'Zeiss look' or a 'Medium Formal look')? Or maybe I'm just imagining it :)

Regardless, really enjoying using the 75, 90 and 165 LS lenses on my 645z.
Forum: Troubleshooting and Beginner Help 05-10-2016, 03:17 AM  
645D + SMC 645 LS 75mm F2.8
Posted By glass
Replies: 6
Views: 1,107
Set it to O.
Then Cock the shutter by twisting the lever at the front of the lens. This opens the leaf shutter.
Now you can use it as a normal lens.
Forum: Pentax Medium Format 05-01-2016, 10:50 AM  
Pentax 67 165mm Leaf Shutter doesn't always fire in Auto Aperture
Posted By glass
Replies: 19
Views: 2,292
Thanks. Apologies, I'm new here - who is Eric and where do I find his email address?
Forum: Pentax Medium Format 05-01-2016, 12:50 AM  
Pentax 67 165mm Leaf Shutter doesn't always fire in Auto Aperture
Posted By glass
Replies: 19
Views: 2,292
I have a number of other LS lenses. As you say, operation is quite straightforward. I can replicate the problem off-camera by sliding the aperture tab on the back of the lens mount - in MANUAL mode the cocked shutter fires as expected, in AUTO mode the cocked shutter only fires intermittently. The aperture slide tab feels a bit stiffer and the trigger point is further around when in AUTO mode.

So my question isn't about technique or operation, but rather if the problem I am experiencing with my lens anybody else has had, or may know what the problem is.

I bought the lens on eBay and got a good price, optically and cosmetically the lens is really nice, but if it is going to be expensive or impossible to fix the LS firing in AUTO mode issue, I'll send the lens back.
Forum: Pentax Medium Format 04-30-2016, 04:39 PM  
Pentax 67 165mm Leaf Shutter doesn't always fire in Auto Aperture
Posted By glass
Replies: 19
Views: 2,292
Thanks, but I don't mean aperture priorty mode (which is an in-camera metering mode).
I mean the big toggle switch on the lens that says MANUAL and AUTO. When set to MANUAL the LS fires, when set to AUTO it only intermittently fires.
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