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Forum: Flashes, Lighting, and Studio 06-17-2020, 01:25 PM  
Advantages of P-TTL over "Auto" Mode
Posted By mcgregni
Replies: 20
Views: 900
A very interesting thread! Thanks to all the contributors so far who have made so many great points.....

For me, in my own limited experience with the AF280T and M series lenses, the most significant distinction between 'Auto' mode flash and P-TTL is control over the balance of flash and ambient exposures.

P-TTL provides a direct and functional workflow for independently controlling the ambient and flash exposures.... (flash exposure controlled by flash compensation, and ambient controlled by the 3 key settings of ISO, Aperture and time value).

So long as you choose an appropriate camera mode, such as M, to exert direct control over your ambient exposure, and you are working within the distance range that your P-TTL flash can correctly expose for, then you have tools to finely tune your flash and 'background' balance, in half or even third stop increments.

Try that in Auto mode! The flash output in auto mode does not self adjust to compensate for any changes to the ISO or aperture settings on the camera, so trying to achieve a specific balance will quickly become an act of contortion and will prove impossible in many configurations and lighting conditions. Each change to ISO and Aperture on the camera will affect the flash exposure recorded making any light balancing attempts futile.

A member earlier wrote about P-TTL flash exposures using the camera metering modes..... I'm not sure about that? I have not been aware of such fineries on our Pentax cameras and had thought that P-TTL only used the Matrix mode. This could be a reason that A type lenses are not always reliable as they cannot utilise the matrix system. However it stands as something to be tested more thoroughly and I would be pleased to be corrected.
Forum: Flashes, Lighting, and Studio 02-15-2020, 09:33 PM  
Sticky: Comprehensive Pentax Flash Guide
Posted By mcgregni
Replies: 52
Views: 40,296
Thanks for the message and I'm pleased the guide continues to be useful! There have been a lot a developments over the last few years with a wider range of third party choices for Pentax flash photographers, and most of the attention is on the newest flashes and trigger products from Godox.

But getting to grips with a Pentax flash both on and off camera is still a great starting point for those new to flash, so there's still a need for a Pentax specific resource to help. I'm only sorry I'm not a YouTuber, where no doubt the info would reach many more people.... I'm afraid I'm stuck in the world of the written word, which sadly less and less people these days seem able to learn from.

But it's always nice to hear from those who continue to enjoy and benefit from the advantages of a written guide!
Forum: Flashes, Lighting, and Studio 12-06-2019, 03:06 AM  
Pentax K-3 and 360FGZ Flash troubles
Posted By mcgregni
Replies: 14
Views: 580
Whether or not a flash can output enough light for good exposure depends on its potential power (guide number), ISO, aperture and distance to subject.

You havent given any of that information, which suggests you may not be considering it all....?

We need to know what the ISO, aperture and flash to subject distance are when it is not exposing correctly, and the mode you are using on the camera that is giving you those settings.
Forum: Flashes, Lighting, and Studio 12-05-2019, 02:26 PM  
HSS using multiple Pentax flashes
Posted By mcgregni
Replies: 17
Views: 979
The older flashes here have a sliding Flash Mode switch (Leading Curtain, Trailing Curtain, Contrast Control, HS Sync). This should be set to HS when working as an on camera Master/Control unit.

This sliding Mode switch should be returned to the left most position (leading curtain sync) for all slave mode operations, including HSS. So only the on camera unit is set to HS mode.

The incompatability of being able to set HS mode on the slider while attempting to use Slave mode on the older flashes is not possible on the newer MkII model with its more modern interface.
Forum: Troubleshooting and Beginner Help 11-19-2019, 12:37 AM  
Is a 'Fast' lens stopped down the same as a 'slow' lens at the same aperture?
Posted By mcgregni
Replies: 37
Views: 1,966
The more I read this the more I find the terms "fast" and "slow" to be very strange ways to describe maximum aperture openings!
Forum: Flashes, Lighting, and Studio 10-09-2019, 07:17 PM  
Sticky: Comprehensive Pentax Flash Guide
Posted By mcgregni
Replies: 52
Views: 40,296
Things keep moving on in the world of flash, and compatibility with Pentax cameras is increasing. That's a good thing, but it doesn't make things any simpler in terms of choices and options!

I hope you get things up and running easily Les, and please come back to the forum with any questions.
Forum: Pentax SLR Lens Discussion 08-29-2019, 02:19 AM  
Why persist in using legacy manual lenses
Posted By mcgregni
Replies: 156
Views: 9,285
There's good and not so good examples within both the old Manual types as well as newer AF lenses ...... we should try to ensure we get hold of the good ones if we can! For me, on a limited (zero now!) photography budget, my legacy manual focus lenses provide a route to top quality IQ without the expense. In general I have found it important to use lens hoods which can improve contrast, but also I recomend RAW captuure and careful editing to get the best out of the image files with old legacy lenses.


Here's a link to a photo thread of mine on PentaxUser.com, all shot with the M75-150 F4.0 .... I simply can't afford a modern zoom that could come anywhere near these sort of results, and these are taken with a 10 year old camera, the K7 .....


Kensington with the M75-150
Forum: Troubleshooting and Beginner Help 08-28-2019, 03:52 AM  
K-x flash question
Posted By mcgregni
Replies: 2
Views: 492
The max sync speed on the aps-c Pentax models is actually 1/180th sec, so a basic manual radio trigger will not send a fire signal beyond that setting.
Forum: Flashes, Lighting, and Studio 07-10-2019, 03:37 AM  
Three flash setup Pentax K-p, Yongnuo YN560 III and IV , AF540FGZ II
Posted By mcgregni
Replies: 14
Views: 1,109
Good idea Clackers, but even I myself back away from referring people to them now.

Reading up and studying things in a written format is seeming more and more like a lost art. It's my impression that the vast majority of newer people here really just want to find out things from YouTube videos. And also they often only want to see a video that answers their exact specific concern, and generally are not interested in a written guide that builds an overall solid base of knowledge.
Forum: Flashes, Lighting, and Studio 07-09-2019, 12:56 AM  
Three flash setup Pentax K-p, Yongnuo YN560 III and IV , AF540FGZ II
Posted By mcgregni
Replies: 14
Views: 1,109
Yes, the term "channels" is probably most commonly associated with television networks, so it's not surprising that it only adds to any assumptions about how the flashes communicate.

"Wireless Channel" as a setting reference does not include a definition of exactly what the communication technology is, so it can be used for a range of system types. It's just one of those things that needs some pre knowledge or research before diving in and using the equipment.

We don't have any documentation to guide us that I'm aware of, but my assumption is that the channel setting must be included in every pre flash as part of the coded optical signals, so that only those flashes set to the same channel will react to those pre flashes.
Forum: Flashes, Lighting, and Studio 07-07-2019, 11:53 PM  
Three flash setup Pentax K-p, Yongnuo YN560 III and IV , AF540FGZ II
Posted By mcgregni
Replies: 14
Views: 1,109
"Epic" fail....? I'd say there's been a few even bigger ones reported here over the years....:lol:
Forum: Flashes, Lighting, and Studio 07-07-2019, 05:30 PM  
Three flash setup Pentax K-p, Yongnuo YN560 III and IV , AF540FGZ II
Posted By mcgregni
Replies: 14
Views: 1,109
We certainly don't have "WiFi" as a control technology for flashes with our Pentax cameras, that's right Inkista. It's likely I think that the OP is confusing the terms WiFi and Wireless, and has not considered the matter of flash communication technologies or read up on it.

I think we need to be told exactly how the flashes are being triggered, ie if its an on-camera flash then what one exactly, and what wireless mode is set. The fact that he did not specify this suggests he did not appreciate the significance of the on-camera flash settings.

It may also be that he believed the communication to the flashes is provided by a (non existent) internal radio system, and not by the optical signals from the camera flash.
Forum: Flashes, Lighting, and Studio 06-29-2019, 12:23 AM  
Cactus RF60x Wake Up?
Posted By mcgregni
Replies: 29
Views: 1,569
Unfortunately they don't respond to radio signals to wake up. You can press any button on the flash unit to wake it up..... I usually use the Next button. All settings remain unaffected, and you have options within the menu to adjust the sleep timeout setting.
Forum: Flashes, Lighting, and Studio 06-19-2019, 12:36 AM  
Wireless Trigger Pentax K-r & YN585EX
Posted By mcgregni
Replies: 9
Views: 1,130
The on camera wireless flash mode should not be a factor here.... In theory both master and control modes should work OK to trigger the slave flash.
Forum: Flashes, Lighting, and Studio 06-18-2019, 04:03 AM  
Normal HSS vs Powersync on RF60x
Posted By mcgregni
Replies: 24
Views: 1,394
Power sync mode with the V6ii is to allow you to use non HSS flashes beyond max sync speed..... A poor man's HSS!

But as already explained by the others, in certain configerations and set ups it will produce more output, although with possible banding or uneven coverage.

It is a function of the radio triggers, not the flash. By definition there is no power control in the mode, as it automatically sets max power..... The flash level is controlled using other parameters, ie aperture, ISO and distance. Therfore it is not as convenient or easily manageable as HSS.

There's not much point to it when using an HSS system IMO..... You've got a V6ii and RF60x, so you're not a poor man!!
Forum: Flashes, Lighting, and Studio 05-30-2019, 03:36 PM  
Need help with HSS on my Godox V860ii & X1 T2.4G
Posted By mcgregni
Replies: 8
Views: 811
And there was me thinking all this time that HSS off camera was only complicated with Pentax cameras! :D
Forum: Flashes, Lighting, and Studio 05-17-2019, 01:32 PM  
AF360FGZ II --or-- AF540FGZ II for K-1
Posted By mcgregni
Replies: 6
Views: 852
You might find this online tutorial I did with the Pentax "540" flash and HSS interesting ....


A Practical Look at High Speed Synch
Forum: Flashes, Lighting, and Studio 04-07-2019, 03:31 AM  
YONGNUO YN585EX Wireless Camera Flash
Posted By mcgregni
Replies: 45
Views: 8,438
When combined with good user knowledge and some experience, the ancient P-TTL system can produce excellent consistency and reliable results. ... But of course, I agree with ClassA that we need to understand and work within its liimitations.

Thanks to the Cactus XTTL system I now enjoy this excellent consistency and reliable fine control even with multiple off camera flashes in P-TTL mode.

I also mostly use M camera mode combined with P-TTL in order to gain the needed control over ambient and flash exposure levels.
Forum: Flashes, Lighting, and Studio 03-14-2019, 02:36 PM  
Xpro-P TTL Wireless Flash Trigger for Pentax
Posted By mcgregni
Replies: 286
Views: 32,798
Glad to hear the Slow Speed Sync can work with the trigger and AD200. Its an interesting "flash mode", because it is not a mode that affects the flash really at all, but rather the camera behaviours. My understanding is that standard "Flash On" mode is really designed for simple flash only scenes, ie where there is no real attempts to balance ambient and flash light, or outdoors in daylight then only for the most basic fill-in situations. The shutter speeds are related to lens focal lengths and designed to avoid camera shake, assuming handholding. So it is sort of "snapshot" mode. Indoors in low light this mode can produce the typical "party" snapshot look, with bright flashed faces and dark surrounds.


Slow Speed Sync assumes that the photographer wants to take more control and combine a mix of ambient and flash exposures, well suited to indoor events or the classic low light portrait outdoors with a city skyline in behind. The camera manual now warns us to ensure the camera is steadied or on a tripod, as shutter speeds will likely not be hand-holdable.
Forum: Flashes, Lighting, and Studio 03-14-2019, 02:24 PM  
Pre readings differ from Post Playback EXIF under these conditions... what gives?
Posted By mcgregni
Replies: 29
Views: 1,446
Yes, its good to acknowledge that flash output combines with ambient brightness, so the two are effectively slapped on top of one another. And there is a risk of blow out where flash is introduced on top of, for example, an already naturally bright face ..... however, I wonder if it may be over-promoting the sophistications of our P-TTL metering system a bit too far to suggest that the system can recognise when a flash cannot reduce its output sufficiently, and consequently take a decision to use shutter speed (if allowed) to reduce ambient to a level that would allow the flash to expose correctly ...? That does sound rather far fetched, however of course there's no proof about this as we lack any technical information about this sort of thing.


It sounds to me more like the sort of considered and assessed decision a photographer would have to make when finely tuning things using manual mode!
Forum: Flashes, Lighting, and Studio 03-14-2019, 10:52 AM  
Xpro-P TTL Wireless Flash Trigger for Pentax
Posted By mcgregni
Replies: 286
Views: 32,798
For these modes, if needing to free the shutter speed restrictions then switch the Camera Flash Mode to Slow-Speed Sync.... this is most effective indoors and in low light to create a true balance of ambient and flash exposures.
Forum: Flashes, Lighting, and Studio 03-14-2019, 10:43 AM  
Pre readings differ from Post Playback EXIF under these conditions... what gives?
Posted By mcgregni
Replies: 29
Views: 1,446
Peter is right with this; its important to keep emphasising that exposure time does not influence the flash exposure level in normal operations .... only in HSS mode will exposure time have an effect on flash exposure.


If the meter detects an overexposure situation even though the flash would output its lowest possible level, then it would need to adjust another variable, ie aperture or ISO, in order to allow a good flash exposure. Which of these varies would depend on the mode of course, and whether ISO is available to vary (auto-ISO parameter settings).


If the need is to reduce flash exposure, and the flash is already at its lowest possible output, then in Av mode the camera only has one thing to vary .... ISO, which would have to be lowered. The only alternative is for the photographer to step back more and increase the distance, then try again with a new pre-flash and test shot.


Regarding shutter speed auto control, then this is determined mainly by the camera flash mode setting and the lens focal length. The system aims to provide a steady handheld shot as the first requirement, and in dim conditions this will result in a poor ambient/flash balance, unless the photographer overrides this with Slow Speed Sync mode.
Forum: Flashes, Lighting, and Studio 03-13-2019, 04:07 PM  
Pre readings differ from Post Playback EXIF under these conditions... what gives?
Posted By mcgregni
Replies: 29
Views: 1,446
Having a flash ready signal going to the camera through the hotshoe changes everything. The metering system has to decide whether it tries to balance ambient and flash exposures, or whether the flash is going to provide everything.

This depends of course on what restrictions on ambient exposure are being imposed by the program line and ISO parameter settings. The Camera Flash mode and lens focal length will likely have the most impact in practice though.
Forum: Flashes, Lighting, and Studio 03-13-2019, 03:08 PM  
Pre readings differ from Post Playback EXIF under these conditions... what gives?
Posted By mcgregni
Replies: 29
Views: 1,446
....


Bruce, be fair please, this is what you told us in your first post, so I think we should be forgiven for understanding you are trying to use Av with Auto-ISO.
You may have said you had changed it later, but the posts are quite long, so its likely that people are responding to the opening one primarily.


No one is denying that its not possible to get some good flash shots using Av with P-TTL modes .... I use that sometimes myself too. But I agree with Steve that it is more suited to "snapshots" .... it is not suited to any situation where we need to take full control over the mix of ambient and flash brightness that is recorded. Whether results in dynamic situations using Av / P-TTL can be more than snapshots really depends on the skill and creativity of the photographer I feel.


Don't forget to check out the impact of the Camera Flash Modes, which can have a major influence on the amount of ambient light allowed to be recorded.


You asked about why the Auto ISO figure was not displayed prior to taking flash pics .... well, its because the figure is not calculated until the pre-flash. And there will be different decisions made based on a range of factors .... camera flash mode, focal length, amount of ambient light are a few of them.
Forum: Flashes, Lighting, and Studio 03-13-2019, 07:09 AM  
Pre readings differ from Post Playback EXIF under these conditions... what gives?
Posted By mcgregni
Replies: 29
Views: 1,446
I keep on with the same mantra over and over, in any Flash threads that concern automated exposures and auto -ISO .... If we want full and secure control over the images (and Professional work always demands this, regardless of the scenario), then we cannot rely on auto exposure parameters in addition to our P-TTL flash levels.

P-TTL itself, by itself, is a good thing and a useful aid to efficiency, but only when its the one single variable to focus on. Automated flash metering needs a solid, fixed base in terms of the ambient EV, not the least in order to allow the photographer to see clearly the precise effect of their compensation adjustments. Trying to view and assess the impact of multiple automated setting responses, as well as juggle two independent compensation inputs ....well, it's all too much and bound to lead to confusion and inconsistently exposed shots.

I do agree that it's good thing to have a basic underlying knowledge of the key aspects of what the automated systems are trying to do, and what they respond to .... That's why I wrote sections in my Guides that cover Camera Flash Modes, the impact of focal length, ambient brightness, program line, auto-ISO parameters etc. But to understand these basic principles is to ultimately appreciate the liimitations of such an automated approach to what is a very complicated thing; the balance of light and darkness in a scene, and the creative desires of the photographer who needs to take control of that scene and produce an image that records a precisely controlled mix of ambient and flash exposures.

No tiny camera computer brain can do that
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