Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-31-2012, 09:52 AM   #1
New Member
kynite's Avatar

Join Date: Dec 2011
Posts: 15
Onboard flash with manual lenses

I am using an old Zenitar fisheye on my K-r and when I use flash it is way too powerfull. I have been taking a lot of pictures of people (up close) and they always comment on how strong it is. Is there a way to make it less powerfull? or can I just put a diffuser over it?

05-31-2012, 09:56 AM   #2
Site Supporter
jatrax's Avatar

Join Date: May 2010
Location: Oregon
Photos: Gallery | Albums
Posts: 10,770
You can use a diffuser. Or manually adjust the flash compensation, under the flash button I think though I do not have a k-r but it was there on k-x.
05-31-2012, 10:10 AM   #3
New Member
kynite's Avatar

Join Date: Dec 2011
Posts: 15
Original Poster
Yeah I saw that under the flash, so setting it to -2ev would make it less bright correct? and yeah I am experimenting with some diffusers....
05-31-2012, 10:52 AM   #4
Site Supporter
jatrax's Avatar

Join Date: May 2010
Location: Oregon
Photos: Gallery | Albums
Posts: 10,770
QuoteOriginally posted by kynite Quote
Yeah I saw that under the flash, so setting it to -2ev would make it less bright correct?
Correct. But remember distance is also important. flash power drops with the square of the distance. So when doing manual flash try to keep the distance fairly consistent. I really struggle with getting this correct and have great respect for photographers who did it manually all the time. Take a test shot and check the LCD and adjust the flash comp as needed.

I think you will find that you will get much better results with a hot shoe flash gun rather than the on-board one. Most I think consider the on board to be fairly useless except in an emergency (as in you have no other choice). You can get manual ones for not much money although up to date PTTL ones are very pricey.

05-31-2012, 12:01 PM   #5
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
A similar question is in this concurrent thread: https://www.pentaxforums.com/forums/pentax-flashes-lighting-technique/187985-...ld-lenses.html. Lowell answers it quite well, and I threw in mi dos centavos. Basically, lenses lacking 'A' contacts don't provide the camera with data for calculating flash duration and intensity. Using our pTTL dSLRs and flash with lenses lacking A contacts is a royal pain challenge. The most straightforward approach is just to calculate and hope, with much trial+error. Keep tweaking aperture+shutter+ISO+distance+filters+diffusers, and testing exposures, and chimping and re-tweaking, until you get something acceptable.

Or stick with A-type and AF lenses when using TTL flash -- but that's no answer for we Zenitar lovers. So I cheat. If I need the Zenitar's AOV with flash, I use the DA10-17 @17mm instead. And that's no answer for those lacking that FE zoom. So the answer for you is: shoot and chimp and adjust and re-shoot until it's just right, or at least good enough. Good luck!
05-31-2012, 05:58 PM   #6
Site Supporter
JimJohnson's Avatar

Join Date: Jan 2012
Location: Lake Superior - Michigan
Photos: Gallery
Posts: 2,271
QuoteOriginally posted by RioRico Quote
Using our pTTL dSLRs and flash with lenses lacking A contacts is a royal pain challenge.
So fool the camera into thinking all lenses are 'A' type. There are several threads on this topic. P-TTL flash will then work with a manual lens. You just need to set the same aperture on both the camera body and the lens.
05-31-2012, 06:37 PM   #7
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by JimJohnson Quote
So fool the camera into thinking all lenses are 'A' type. There are several threads on this topic. P-TTL flash will then work with a manual lens. You just need to set the same aperture on both the camera body and the lens.
As has been mentioned, exposure adjustments are needed. Also, it may not work. My first couple attempts failed, and I don't feel like dismantling my K20D again to repeat the attempt.
06-01-2012, 01:06 AM   #8
Veteran Member




Join Date: Jul 2008
Location: Var, South of France
Photos: Albums
Posts: 1,071
QuoteOriginally posted by JimJohnson Quote
So fool the camera into thinking all lenses are 'A' type. There are several threads on this topic. P-TTL flash will then work with a manual lens. You just need to set the same aperture on both the camera body and the lens.
NO!!!

For this to work, you'll have to:
- short the A pin (using some soldering, or aluminum foil).
- disable the aperture link between the lens and the camera (best method is by mounting your lens only halfway).
- select the widest available aperture on the camera, no matter what aperture you actually use on the lens.
(Downside of this method is that your viewfinder will darken considerably with smaller apertures)

Non-A lenses cannot be easily transformed into an A lens due to the different aperture link behavior.
Though, with some luck, some third-party lenses can be transformed, as their aperture couplers are behaving just as with an A-lens. The Porst 55/1.2 is such a lens, without an "official" A position but perfectly compliant with the surface-related aperture behavior.

A better way would be to invest in an Auto flash...

06-01-2012, 05:08 AM   #9
Site Supporter
JimJohnson's Avatar

Join Date: Jan 2012
Location: Lake Superior - Michigan
Photos: Gallery
Posts: 2,271
P-TTL flash using a manual lens

  1. 'A' pin shorted on my K-r.
  2. appropriate contact insulators on a mounted 28mm / 2.8 lens to tell camera the available aperture range
  3. camera set to Av (aperture priority), menu C/4 (22), Permitted - "Shutter will release when the aperture ring is not set to the "A" position"
  4. camera turned on, lens length (28) input, built-in flash raised
  5. lens set at f/8.0
  6. camera body set at f/8.0
  7. exposure compensation +/- 0.0
  8. manual focus on my less than glamorous typical test subject (office coffee pot) - the distance is just over 3 feet (1m)
  9. Shoot!

The ONLY post processing on the jpeg produced by the camera is a size reduction. Might I need to do some exposure compensation ? Yes. But test shots are typically pretty easy on a digital camera. And the variability in P-TTL can usually be accommodated with a little post processing.
Attached Images
View Picture EXIF
PENTAX K-r  Photo 
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, flash, k-r, kr, onboard flash, pentax k-r, powerfull
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Onboard Flash Na Horuk Pentax K-r 11 04-19-2012 03:32 PM
Flash with new manual lenses Urmas R. Flashes, Lighting, and Studio 4 04-28-2011 06:43 AM
Is the onboard flash WR? Cambo Pentax K-5 9 12-22-2010 01:10 PM
Nature Just playing around with my onboard flash photolady95 Post Your Photos! 2 08-02-2010 05:01 PM
using onboard flash w/ M-series lenses heatherslightbox Pentax DSLR Discussion 4 03-29-2008 10:30 PM



All times are GMT -7. The time now is 08:46 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