Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-22-2008, 08:13 PM   #1
New Member




Join Date: May 2008
Location: Ontario Canada
Posts: 3
Flash to D cameras

Question
From a newbee

I am wanting to get into digital photograph there are so many questions.
I have posted once before and one of our members had very good info, and was quit helpful.
The question this time is will an nondigital flash work on a digital camera.
This is a list of my equipment, (film equipment )
Will the flash that is listed work on a “D” type system?
Meaning ( Vivitar 285HV Zoom Thyrister Flash)



Pentax Equipment
Spotmatic SPII
Asahi 55mm / 200mm
Auto Alpa 28mm
Sun Tele Zoom 110-180mm
Soligor Auto 2x Converter
Vivitar 285HV Zoom Thyrister Flash


Jim from Ontario

06-23-2008, 04:37 AM   #2
Site Supporter
Site Supporter
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 17,868
There are 2 issues, specificaly trigger voltage and flahs mode

Many older flashes have trigger voltages that are in excess of the capability of modern cameras. By modern, I mean cameras with advanced flash metering including TTL and P-TTL. This goes back a long way in pentax, My PZ-1 (1991 vintage) had TTL flash.


If the trigger voltage is OK, the next issue is modes. Some flashes will not function at other than either full power or in complete manual mode, because the new camera does not support TTL, or the flash does not support P-TTL.

Within pentax, only the *istD and DS support TTL for example. All other pentax DSLRs are P-TTL which uses pre-flashes to measure the light at full apature, as well as communicate with other off camera flashes.

Your vivitar will be TTL at best, and assuming it is safe to use, it would probably only function in manual mode, or if it has its own sensor, Auto mode
06-23-2008, 07:42 AM   #3
Veteran Member
noblepa's Avatar

Join Date: Sep 2007
Location: Bay Village, Ohio USA
Posts: 1,142
Vivitar 285HV is safe

Lowell Gouge is correct that trigger voltage is a concern when using older flash units on new, especially digital, cameras. The concencus seems to be that Pentax dslrs, such as the K10D, can handle up to about 25-30 volts. Some older units have trigger voltages as high as 300 volts, which can fry the electronic flash synch circuitry.

You're in luck, though. The Vivitar 285HV is known to be one that is safe to use. The 285 (not HV model), is questionable, as is the common 283. I have a 283 with a trigger voltage of about 130 volts. Needless to say, I don't use it on my K10D. In fact, Vivitar put the 285HV back in production. It is available new from B & H for $89.95. Just to be safe, check the voltage across the synch terminals with a digital voltmeter.

However, the 285HV is neither TTL nor P-TTL. It can be used in fully manual mode, in which you calculate the f-stop and set it manually, or automatic mode.

In automatic mode, the 285HV has several flash intensity settings. Depending on the ISO speed that your camera is set for, you set the f-stop at a single, fixed value. A thyristor (light sensitive transistor) on the flash unit itself, senses when enough light has reflected from the subject. When that point is reached, the flash shuts off. For this reason, auto flashes have a variable flash duration, from 1/1000 to about 1/50,000 second. The closer the subject, the shorter the flash.

To use the flash on a dslr, you pick your flash intensity and use the calculator on the flash unit to determine the f-stop. Set the camera in manual mode. Set the shutter speed to 1/180 (the max flash synch speed) and the f-stop to what the calculator tells you. Then start taking pictures.

In other words, use it in exactly the same way you would on your Spotmatic. The only difference is that you have a higher synch speed (1/60 on the Spotmatic).

You will probably want to check your exposures in the LCD screen and make minor adjustments to the f-stop.
06-23-2008, 12:13 PM   #4
Moderator
Loyal Site Supporter
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 15,903
QuoteOriginally posted by jimrodman Quote
Question
From a newbee

I am wanting to get into digital photograph there are so many questions.
I have posted once before and one of our members had very good info, and was quit helpful.
The question this time is will an nondigital flash work on a digital camera.
This is a list of my equipment, (film equipment )
Will the flash that is listed work on a “D” type system?
Meaning ( Vivitar 285HV Zoom Thyrister Flash)


Jim from Ontario
My understanding is that the 285HV has a trigger voltage well within the acceptable range for Pentax DSLR cameras.
Your Vivitar is a non dedicated auto flash, so you will be using the camera in manual mode (set the shutter speed and aperture yourself), and then dial in the flash range to match the aperture (or vice versa).
As an example, (numbers are probably wrong, it's been a long time since I used a 285), you would set the ISO of the camera to 200, and set the flash to the "Red" range. Set the shutter speed to X or slower, and the F/stop to f/4.
In other words, you are using it the same way as how you use it on your Spotmatic.

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!
auto, camera, equipment, flash, photography, question, thyrister, vivitar
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: Metz 58 AF-1 Digital P-TTL Flash for Pentax Cameras (US/CAN) Djedi Sold Items 1 09-06-2010 08:24 PM
New to Pentax (and film cameras!) - help with picking out a flash to purchase? crankybird Flashes, Lighting, and Studio 3 01-24-2009 07:42 PM
Suggestion more review databases: accessories (bags flash etc), cameras chse Site Suggestions and Help 2 11-07-2008 09:58 AM



All times are GMT -7. The time now is 03:04 PM. | 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