Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-06-2018, 01:15 AM   #1
Forum Member




Join Date: Jul 2016
Posts: 60
Some questions about flash

Hi all

I have a few questions about flash usage. A few times when using wireless flash I have noticed a black bar on one side of the image. Would I be right in assuming this is a bad sync?

I'm using cheap dumb triggers and a manual chinese flash. How do I calculate what sort of exposure settings to expect with given aperture, distance and such? Is there a way to compensate for a reflector? I'm using a cheap silver umbrella.

Thanks in advance for any help

07-06-2018, 02:18 AM   #2
Veteran Member




Join Date: Jun 2015
Location: South West UK
Photos: Albums
Posts: 1,493
QuoteOriginally posted by jpipg Quote
Hi all

I have a few questions about flash usage. A few times when using wireless flash I have noticed a black bar on one side of the image. Would I be right in assuming this is a bad sync?

I'm using cheap dumb triggers and a manual chinese flash. How do I calculate what sort of exposure settings to expect with given aperture, distance and such? Is there a way to compensate for a reflector? I'm using a cheap silver umbrella.
The first is indeed bad sync. Either because your shutter speed is too high or because the trigger is too slow. A few test shots will allow you to find the sweet spot.


Secondly...it is possible calculate a guesstimate of required exposure...it's much more difficult with a modifier and all much much slower than either using a light meter, or taking a few test shots and adjusting to suit. TTL metering takes much of the guesswork out of it, but with manual flashes you need to do it the old fashioned way.
07-06-2018, 02:33 AM   #3
Forum Member




Join Date: Jul 2016
Posts: 60
Original Poster
Thanks for the info. I think it was the triggers causing a bad sync, I'm careful to keep within the sync speed although the KP lacks an X setting, so I may have knocked the dial for shutter speed.

What kind of light meter is required for this? The meter would have to read the flash light, so is there a meter that can display a reading as quickly as the flash fires?
07-06-2018, 02:41 AM   #4
Veteran Member




Join Date: Jun 2015
Location: South West UK
Photos: Albums
Posts: 1,493
Light meters with flash capability usually trigger the flashes and take a reading at the same time, then display the required exposure. They tend to be pricey, hence why I don't have one and can't go into more detail. Since you will probably be fixing the flash power, shutter speed and ISO and only have the aperture to vary, finding the right exposure by trial and error is a fairly quick job.

07-06-2018, 02:47 AM   #5
Veteran Member
amoringello's Avatar

Join Date: May 2008
Location: Virginia, USA
Photos: Gallery
Posts: 1,562
Yes, not uncommon. Some triggers are not as quick as advertised. Even the expensive ones.
I had to argue the math to Elinchrom a few years ago. Their original Skyport remote used to be advertised to handle 1/1000s, in reality is was 1/125s. Well below Pentax 1/180 at the time. I believe they advertise a much different number now.
FYI, There is nothing wrong with 1/125s or slower if your flash(es) are significantly overpowering the ambient light. This should be a goal in most cases, but cannot always be avoided. The slower shutter can be an issue if that is an important consideration for the types of photos you take.


Most light meters will have a mode where they wait patiently for a change in light. The speed of the flash sync doesn't matter. You simply fire the flash manually and the meter detects the light and reports it's values. Or just go the cheap route, and adjust the lights and/or the camera exposure until the image comes out correct. (SD card space is cheap).

---------- Post added 07-06-18 at 05:50 AM ----------

QuoteOriginally posted by jpipg Quote
Thanks for the info. I think it was the triggers causing a bad sync, I'm careful to keep within the sync speed although the KP lacks an X setting, so I may have knocked the dial for shutter speed.
Ricoh/Pentax does not allow the flash pin to fire above the shutter sync speed. So normally you don't have to worry about setting your shutter speed too fast, as the flash won't even fire if you do. But the flash system might not react quickly enough and can force you to slow down your shutter anyway.
07-06-2018, 04:05 AM   #6
Loyal Site Supporter
Loyal Site Supporter
macman24054's Avatar

Join Date: Aug 2013
Location: Axton, VA
Photos: Gallery | Albums
Posts: 461
I have a set of cheap triggers. Of the 4 triggers only two will allow me to shoot at 1/180. The other two i have to shoot at 1/125. I have a set of Cactus V5 and I can shoot them at 1/180 all day with no issues. I guess it is just cheaper build and not very good quality control.
07-06-2018, 07:37 AM   #7
Veteran Member
CarlJF's Avatar

Join Date: Sep 2014
Location: Quebec City
Posts: 1,185
QuoteOriginally posted by macman24054 Quote
I have a set of cheap triggers. Of the 4 triggers only two will allow me to shoot at 1/180. The other two i have to shoot at 1/125. I have a set of Cactus V5 and I can shoot them at 1/180 all day with no issues. I guess it is just cheaper build and not very good quality control.
Same for me. I have a set of cheap NPT-04 triggers and, according to the specs sheet, they're not rated to go faster than 1/125. But so far they have worked fine at 1/180... I guess 1/125 is only the fastest speed they're guranteed to work.

07-06-2018, 09:59 AM   #8
Pentaxian




Join Date: Sep 2012
Location: NY
Photos: Gallery | Albums
Posts: 6,034
You can start by using something like 1/4 power on your flash and check the aperture on the flash to make sure it is covering the subject the way you want it to. On your camera you can set the shutter speed at what your remote triggers need for sync and go from there. If you have a handheld light meter, you could just hold it in the area you want you be measured and fire your camera for an activation of the lighting being triggered. If you do not have a handheld light meter, then fire some test shots of the subject and review the histogram and/or the image on the rear lcd of the camera. The histogram will tell you what your lighting is doing, and if you have enough shade to view the review image itself, it will give you an idea of what you are doing.

I have 6 Cactus V5 triggers and they perform (5 of them used in this set up) at a 180 sync speed along with my K-3 II, 3 AF360FGZ flashes, and a Yongnuo YN585EX flash. They also do an excellent job.

Last edited by C_Jones; 07-06-2018 at 10:11 AM.
07-06-2018, 10:14 AM   #9
Veteran Member
mcgregni's Avatar

Join Date: Sep 2012
Location: Surrey, England
Posts: 2,603
We're all in a much better place now, in this digital age, than the film users of yesteryear with their flash meters and calculations. I very much doubt that I could ever have learned much about flash, or got proficient with it, back in my film days .... the lack of instant review, not knowing whether the flash had exposed OK or not, would have stifled all experimenting and testing because of the film costs.


Of course we could all still be doing Manual flash calculations properly, and using sophisticated flash meters now, just as before, and probably deriving some great personal satisfaction out of nailing things with our mental powers and skill ..... but, the truth is, now we don't need to.


We can now guess, fiddle, fudge, nudge and tweak our way to the perfect exposure, and have it all confirmed on the histogram for reassurance. There are degrees of education to our guessing, fiddling, fudging, nudging and tweaking, and so experience will make all of this efficient and nearly instant. You gain a "feel" for the power settings needed for certain standard exposure configurations .... for example, I know that for my usual portrait set-up, ISO 100, F9.5, 1/180th, I need my Main flash (with softbox) set to 1/4 power, and my fill light on an umbrella set at 1/16th. This will produce near perfect exposure for most subjects, so long as the distances from the flashes to the subject are always the same. Because I'm doing this in the same spot in my living room, it always stays the same.


If I am using bigger distances then I will guestimate the impact of this, and perhaps try a one stop increase on both flashes. Also, if I decide to use a higher ISO or wider aperture, then I just have to remember to make the corresponding adjustment (reduce power) on each flash ..... I wouldn't even need to take test shots for this, but I admit I still usually do, as its free!


Bouncing light and reflecting it will be more difficult to guestimate quickly, and the scenario and bounce distances might be changing .... that's why for bounced on-camera flash I always use P-TTL. There would be more tweaking and checking things with a manual flash, so automatic is more efficient. But for static, controlled set-ups, especially where you are repeating things and re-using the same positioning again and again, then Manual mode, with a quick check on the histogram, is quite easy to do now .... a little experience will make it all fall into place.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, fire, flash, light, pentax help, photography, questions, shutter, sync, triggers, troubleshooting
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Questions, questions, questions (PZ-1 and P3) dakight Film SLRs and Compact Film Cameras 12 09-06-2014 06:23 AM
Slide dup/scanning. Did research. Some insight. Some questions. A bit lengthy. MD Optofonik Film Processing, Scanning, and Darkroom 12 04-16-2014 06:30 PM
Some Questions About Some Photographic Equipment For The K1000SE photographyguy74 Pentax SLR Lens Discussion 13 12-13-2013 08:35 PM
Newbie with some questions on some old lenses bigted Pentax SLR Lens Discussion 3 10-16-2011 06:44 PM
Found some free goodies, have some questions XeroX Pentax SLR Lens Discussion 4 08-06-2010 07:34 AM



All times are GMT -7. The time now is 04:11 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top