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07-05-2015, 01:40 PM   #16
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QuoteOriginally posted by BrianR Quote
Please no, don't do that. I use it all the time.
Agreed. No top LCD screen is a dealbreaker for me.

QuoteOriginally posted by philbaum Quote
I haven't really used it that much - So in what situations do you use it??
For me, all situations. I never adjust my camera settings with the viewfinder to my eye. That's just how I roll

07-05-2015, 01:51 PM   #17
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QuoteOriginally posted by philbaum Quote
I haven't really used it that much - So in what situations do you use it??
Pretty much all of them.

It's easily readable in full sunlight. The ones with back lighting are readable by night (and imo much gentler on the eyes than the back lcd). It's comfortably accessible when the camera is hanging from my neck (rear lcd, even a tilting one, is not), and this is almost always where my camera is when I'm adjusting settings (or on a tripod). It's the first thing I look at when I pick my camera up and flick the power on - drive mode, shutter, iso, and aperture, all at a quick glance. Those are my most changed and most important settings to have as a quick reference.

I suppose I could get used to a camera with no top lcd if I had absolutely no choice, but I don't want to.
07-05-2015, 02:34 PM   #18
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Coming from an E3 camera that had both an articulating screen and a top screen, I used the top screen a lot more than one would think. Take your LCD and tilt it towards sunlight and see what you get. It was nice to be able to read my settings quickly through the top LCD than trying to shade my articulating one enough to read it.
07-05-2015, 08:58 PM   #19
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QuoteOriginally posted by philbaum Quote
Sony's mirrorless started out with the Nex models and had a synch speed of 1/160s. When they introduced the A7 series - they bumped up the sync speed to 1/250s. Yet these are still the most inexpensive FF cameras one can buy. I don't think Pentax's mechanical shutters are inexpensive considering the high frame rates they are capable of shooting at and how quiet they are.

So i don't think changing the sync speed is such an insurmountable task.
IIRC, the Sonys sync fast when using their electronic shutter. The problem, of course, is the matter of how focal plane shutters work. The full frame is only fully open below a certain shutter speed*. That speed depends on the time it takes for the curtain/blade to traverse the frame. On a Pentax, that time is somewhat faster than 1/360s. How much so is not part of the published specs. So, assuming the true speed is 1/500s (2ms). That should allow shutter sync of 1/250s. Woo! Hoo! Unfortunately, the full frame will only be open an infinitesimally short period of time at that speed. We need to leave the frame open long enough to actually fire the flash. So, the big question at this point is the flash system latency along with the expected flash duration. The traditional convention on 35mm FF has been no faster than about 1/200s for X-sync.

On the Nikon D7100 (the K-3s closest market competitor), the advertised sync speed is 1/250s with a qualified extension to 1/320s. From Nikon.com:

QuoteQuote:
X=1/250 s; synchronizes with shutter at 1/320 s or slower (flash range drops at speeds between 1/250 and 1/320 s)
Yes, the effective guide number drops above 1/250s and unpredictably so with non-Nikon flashes. 1/250s is 1/2 stop faster than 1/180s. I am not sure, but I believe that both Pentax and Nikon source comparable shutters from Copal. Why Pentax does not step up the additional 1/2, at least for the appearance of parity, is anybody's guess. It may have more to do with the Pentax flash system than anything else.


Steve

* This is an oversimplification. Flash sync at faster shutter speeds is possible, paradoxically, by providing flash with long duration. This was traditionally done with long-burn flash bulbs with the sync signal sent shortly before the start of first curtain travel. The bulb would illuminate for the full duration of the shutter action. Supporting film cameras (e.g. Pentax K-series film bodies) had a special FP sync port.


Last edited by stevebrot; 07-05-2015 at 09:12 PM.
07-05-2015, 09:14 PM   #20
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QuoteOriginally posted by philbaum Quote
Friday - i interviewed with, and got accepted by a really nice gallery in my area. Because its a co-op, there were 5 artists that sat in for the interview. Feels incredible to get that kind of validation.
Congratulations! The bar is set pretty high in Pt. Townsend.


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07-05-2015, 09:16 PM   #21
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QuoteOriginally posted by philbaum Quote
I haven't really used it that much - So in what situations do you use it??
Like he said...all the time. Many of us leave the rear LCD status display off and for night work disable the preview as well...easier on the eyes when doing on on-tripod work.


Steve
07-06-2015, 09:23 AM   #22
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Thanks Steve - I actually joined the Collective Visions Gallery ( Collective Visions | a Gallery of Art ) in Bremerton. I divide my time between Bremerton and Port Townsend. While Collective Visions is the Best in Bremerton, Port Townsend has 4 "best" galleries. But in Feb every year, CV holds an "all-Washington State Juried Show" with lucrative prizes. That show in February is AWESOME. Unfortunately the Gallery members get no special consideration when getting thru the judge each year. But it is a fun show to see.

I've discovered that i was partially wrong about the Sony Nex6 sync speed and how that operates. When i pop up the built-in flash, turns out that i'm unable to increase the shutter speed above 1/160s. Somehow, the camera reads that there is an approved flash attached. But when i install a Cactus V6 manual flash radio trigger, or a Cactus manual flash, then I am able to raise the shutter speed above 1/160s. At a lens aperture of f2.8 (didn't test any others), i was able to get a full cropped frame image at a shutter speed of 1/200s, Sony 50m f1.8 e-mount lens. At a shutter speed of 1/250s, a dark top edge of the frame occurs. So a 1/4 step improvement in the sync speed isn't a massive improvement, but its interesting.

Thanks to every one that participated in this discussion. Interesting, especially on the shoulder LCD.
07-06-2015, 10:46 AM   #23
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QuoteOriginally posted by Oldbayrunner Quote
I find it amusing that some I presume research the product they are buying, research what it's specifications are, research it's good points and comparative negatives vs other products, buy the product then beseech the manufacturer to change to something they want differently found in other products that have the feature(s) they want and could have bought in the first place. It is a known given Pentax cameras, as mentioned due to their shutter designs, have always had no greater than a 1/180 flash shutter limitation, ever. If they really wanted to produce a higher shutter speed sync I am pretty sure in their over 50 years of Slr/dslr manufacturing history they would have by now. I also am pretty certain if they didn't have the feature that stops one from taking a photo beyond that, unless using HSS, then we would have who knows how many threads on Pentax's lack of prevention for photos taken with the out of sync black lines, which I image is one of the reasons why it is included in the first place.
My P-Z1P has 1/250 flash sync speed.

07-06-2015, 12:34 PM   #24
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QuoteOriginally posted by Dipsoid Quote
My P-Z1P has 1/250 flash sync speed.
Good work adding that information to the mix. The higher models on the Z/PZ series bodies support 1/250s. Pentax stepped back to 1/180s with the MZ-S and 1/125s or 1/100s on the other MZ/ZX series bodies*. The run-down looks something like this:
  • 1/250s : Z/PZ series (some)
  • 1/180s : MZ-S, dSLRs (most)
  • 1/150s : *ist D
  • 1/125s : MZ/ZX (some),*ist film, ME Super, ME-F, Super A/Super Program, K2/K2 DMD
  • 1/100s : Program A/Super A, P-series, M-series (most), Z/PZ-series (most), MZ/ZX (most)
  • 1/75s : LX
  • 1/60s : A3/A3000, MX, K-series (most), Spotmatic (all versions)
  • 1/50s : All other horizontal-run shutter bodies with X-sync support
As a trivia note, my Kiev 4A (Contax II clone) has a vertical metal shutter boasting an X-sync speed of 1/25s. Leica film cameras never broke the 1/50s barrier.


Steve

* All AF Pentax film and digital cameras (also a few non-AF bodies) were designed to operate using some version of the digital flash control protocol supported by current generation Pentax-brand flashes. Yes, the base protocol is that old (1987) with extensions for features such as P-TTL added later.
07-06-2015, 07:46 PM   #25
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This old hoary "increase the flash sync by just a firmware update" comes up on PF often.
As far as I know, the mainstream Pentax K mount dslr cameras still use the venerable focal plane curtain shutter.

At long exposure times, the curtain snaps open to expose the whole film/sensor frame for approximately the nominal time , eg 1/60th sec.
To illustrate this, Photo 1 below, simulates by winding the curtain open with the film back removed.
If a flash fires while the curtain is fully open like this, the light reflected by subject from the flash will illuminate the whole frame, reasonable evenly ( by radial cos^4, etc)

As a shorter exposure time is called for by the user, the curtain changes to a slit.
To illustrate this, Photo 2 below was with the 1/1000th second slit held stationary by a clamp. In operation this slit travels at very constant velocity across the film plane from top to bottom.
On this old 4x5 camera, the slit is about 4mm wide and travels 100mm . So for 1000th of a second ( 1 millisecond) integration time on the film/sensor, the travel time of the slit.
is approximately 1 * 100/4 = 25 millisecond, or 1/40th sec in photographers' parlance.

If we wanted to expose this 1000th sec exposure across the frame, we would need a flash burn time of more than 1/40th second. ( which is about what they did in the old days! )

In that case the flash will illuminate the film/sensor by cos^4 in X and hopefully about the same in Y, provided it gives constant illumination for the whole time and the curtain is very close to the sensor.

Today it is called something like HSS - high speed sync, where the electronic flash tube is pulsed repeatedly during the travel time to give approximately even illumination in time.

I hope this humble explanation helps those who ask the same question about flash sync on fp shutters.
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07-07-2015, 03:00 AM   #26
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QuoteOriginally posted by wombat2go Quote
This old hoary "increase the flash sync by just a firmware update" comes up on PF often.
Just to be clear, that's not what the OP was asking for via firmware. He, and many others like myself, want the signal to fire the flash to be sent at any shutter speed. Let us deal with how well it syncs or what else we plan to do with the signal (such as trigger remote cameras). I'd never expect this to be enabled via firmware on older cameras (though it may be possible), but I can't imagine it would be terribly difficult in the grand scheme of camera design to add it to new models without any hardware changes.

This isn't the same as demanding a higher sync speed, which would of course be nice but obviously involve more technical changes or wizardry.
07-07-2015, 04:44 AM   #27
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QuoteOriginally posted by BrianR Quote
He, and many others like myself, want the signal to fire the flash to be sent at any shutter speed.
Do you mean at the center pin of the hot shoe?
Well that would raise the question as to when during the slit travel the pulse would come.
It is difficult to image any use for such a pulse. And I suppose users would be unhappy with whatever timing was used.
Other users might be unhappy that their flash fired and spoiled the photo.

Futhermore, for your request, the Pentax cameras actually do provide a high speed sync to the hot shoe at speeds above 1/180th
It is for "high speed sync" Refer for example to the K-01 manual page 222
AF360FGZ manual pages 31 and 42.
07-07-2015, 09:01 AM   #28
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QuoteOriginally posted by wombat2go Quote
Do you mean at the center pin of the hot shoe?
Yes, that is what he means. The use case (troubleshooting) is a bit of a corner case, but there are also people who will intentionally use flash at greater than the X-sync speed for special purpose and simply crop out the black bar. As for timing...I believe the convention is to fire at the end of first curtain travel.

I view this as one of the hundred of so fairly reasonable suggestions for configuration or firmware features that are posted to this site every year. Whether any will make it into the feature set for future cameras is a toss-up. One may be well-assured that almost none will be applied to current models, if for no other reason that the development cycle would carry over to the next product release.


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07-07-2015, 09:32 AM   #29
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QuoteOriginally posted by wombat2go Quote
Do you mean at the center pin of the hot shoe?
Well that would raise the question as to when during the slit travel the pulse would come.
It is difficult to image any use for such a pulse. And I suppose users would be unhappy with whatever timing was used.
Other users might be unhappy that their flash fired and spoiled the photo.

Futhermore, for your request, the Pentax cameras actually do provide a high speed sync to the hot shoe at speeds above 1/180th
It is for "high speed sync" Refer for example to the K-01 manual page 222
AF360FGZ manual pages 31 and 42.
I haven't used Pentax flashes for years - strobist approach and manual flashes now. I have a Metz compatible flash lying around somewhere but I'd have to knock off the dust first. To see how strobists are using the center pin, see Class A's review of the Cactus V6 triggers and RF60 flashes in the Lighting forum. 100 yd range, fully adjustable zoom and power remotely. I buy both Pentax and Sony cameras, and can switch my manual flashes and radio triggers from one to the other without buying new flash equipment. Once i have a scene set up for theatre promo's, my friend with his Canon was able to use my same flash equipment by slipping the radio trigger on his camera. Never did like how pttl made folks blink.
07-07-2015, 10:00 AM   #30
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Using the Adaptors Fg and cable F5p I can see the transactions on the data pin between the K-01 and the AF360FGZ.
It does not look like serial ascii, it looks like time division handshaking initiated by the AF360.
There appears to be a pulse in the train that stays high when the shutter is pressed.
If so it should not be difficult to do a little logic board and generate a galvanically isolated pulse via an optocoupler.

There is an old thread on PF where some guys started something like this although no results were reported.
A small search did not show a hack of the Pentax hotshoe although there are some for other cameras.
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