Wednesday, September 1, 2010

High Speed sync output tests....

(warning, this is a highly geeky post)
Ever wondered what the light coming out of your Nikon flash looked like output-wise when in Auto-fp High Speed Sync? Here are actual samples as taken with my pocket DSO and a photo-transistor.
I did this to put to rest some conjecture out on the internet. This is a proper method to understand what flash output is doing vs time. We can see output intensity and duration for a given shutter speed.

I tested this using a D90 I had lying around combined with an sb-800 flash set into manual power. I handheld the camera and aimed it towards the photo-transistor that was connected to the scope. The total output could be varying as I was handholding it and readjusting, but the graphs shape and duration are valid.

What the graphs will show are the following.

1) Output is practically continuous as the flash is pulsed for the duration necessary ensure a proper exposure.

2) When additional power is requested in auto-fp, the intensity of the flash is increased.

3) Full frame sensors use short auto-fp durations for the same shutter speed as compared to crop bodies.


Nikon D90, SB-800 1/128 @ 1/200th sec shutter (Clipped output going up, a regular flash pulse is a huge output of light that tapers off)


Nikon D90, SB-800 1/128 @ 1/250th sec shutter


Nikon D90, SB-800 1/128 @ 1/500th sec shutter


Nikon D90, SB-800 1/128 @ 1/1000th sec shutter


Nikon D90, SB-800 1/128 @ 1/2000th sec shutter


Nikon D90, SB-800 1/128 @ 1/4000th sec shutter


Now for a comparison of more power and also a full frame body.

This shows the D90 at 1/128th power and 1/32nd power, it is hard to make out but overall power is increased out. I noticed this when I shot it at full power, but didn't document it with a picture.

The last image shows how the light output waveform is different for the same shutter speed with a different body. I utilized my D700 for this test. In retrospect I should have made a test with my D300s as well to see if the two crop body shutters are different mechanically.

Nikon D90, SB-800 1/128 @ 1/1000th sec shutter


Nikon D90, SB-800 1/32 @ 1/1000th sec shutter


Nikon D700, SB-800 1/128 @ 1/1000th sec shutter (Note shorter duration)

21 comments:

  1. Very useful tests , thanks for taking the time !

    ReplyDelete
  2. Would setting the flash power level at 1/2 make a substantial difference on the test results?

    How about 1/1?

    ReplyDelete
  3. Cool Post. D90 vs. D700 effect might not be due to APS-C vs. FF but due to the D70o's faster shutter (1(250s vs. 1/200s X-sync)

    ReplyDelete
  4. Thank You So Much for sharing. Check out our Background removal service website.

    ReplyDelete

  5. Superb article, man!! you are really included a real advance area of knowledge I expect for may days. Hope you more article on it creates & let us to see.
    After all many thanks for this post.
    http://www.designercountry.com/

    ReplyDelete
  6. That was a remarkable and complete article… all of the tips tallied and explained will be valuable for the people who are wise enough to tap from it. Any business nowadays without electronic long range informal communication sign and proximity may not make it to the farthest, and adventure additionally is a bit of the best approach to accomplishment in business. Continue doing amazing.

    http://www.designercountry.com/

    ReplyDelete
  7. ZKTeco has been providing its services in Bangladesh for a long time. Their products are very nice. There are lots of products, k50 zkteco T&A and Access Control Terminal are among them.

    ReplyDelete
  8. Awesome creation. Great work. Thanks
    If your need any kind of Photoshop retouching services you can visit us at Click here

    ReplyDelete
  9. I impressed by the quality of information on this website. There are a lot of good resources here.
    Photo Retouching Services

    ReplyDelete
  10. Marvelous post!!! Your blog is really outstanding. Thanks a lot for sharing such a wonderful post.
    Clipping Path
    Clipping Path Service

    ReplyDelete
  11. Really lovely article it is. Thanks for sharing with us. I find a very good article forphoto retouching online, If you need any help you can contact this site.

    ReplyDelete
  12. Live corporate events have proven to be the best platform for both B2B and B2C marketing efforts. event marketing and how to write a biography for a conference

    ReplyDelete
  13. Rentsbd is a highly professional rental agent for making a successful Office Space Rent In Banani for you. We are one of the best rental and real estate agencies in Bangladesh.

    ReplyDelete
  14. Wonderful analytical post on a technologist perspective on photography and travel photography. Thanks for sharing with us.
    What is others in storage Android

    ReplyDelete
  15. A highly geeky post on a technologist perspective on photography and travel photography. Thanks for showing the graphs.
    Buy Verified Neteller Account

    ReplyDelete
  16. Thank you for your valuable and useful information through the blog.
    I am appreciating with the way you shared the relevant, precious, and perfect information. Furthermore,
    I would like to also keep some sound knowledge of best hyip template.
    so just visit our website and you will get complete Assistance related to HYIP and send me your valuable feedback on our website. You will get immediate assistance.

    ReplyDelete
  17. The photo retouching service provided by Graphic Experts India is amazing! They expertly edit photos, guaranteeing the ideal harmony between unforced beauty and polished expertise. Their experience will make your pictures look flawless. Have faith in them to enhance your images to their fullest!

    ReplyDelete