:: View topic - Videomicroscopy using still cameras in movie-mode?
 Forum Index
An online community devoted to the practices of photomacrography and amateur microscopy..
 
New! Photomacrography2.net
 
This site is no longer available for posting or registering new members.
 FAQFAQ   SearchSearch     UsergroupsUsergroups   
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Videomicroscopy using still cameras in movie-mode?

 
This forum is locked: you cannot post, reply to, or edit topics.   This topic is locked: you cannot edit posts or make replies.     Forum Index -> Macro and Micro Technique and Technical Discussions
View previous topic :: View next topic  
Author Message
Thomas Ashcraft



Joined: 31 May 2006
Posts: 25

PostPosted: Sun Jun 18, 2006 3:31 pm    Post subject: Videomicroscopy using still cameras in movie-mode? Reply with quote

I am very impressed with Ralf's Hydra video which he made using a Canon powershot camera in movie-mode.

I haven't seen much written about using snapshot cameras in movie-mode to do videomicroscopy. For example, a Canon Powershot S3 IS 6MP Digital Camera can make a movie at 60 fps QVGA (320 x 240). That certainly seems adequate for capturing fast cilia movements and rotifer coronas and such.

Are snapshot cameras a good way to go for making short 10 and 20 second microscope movies? Are there drawbacks?

Thanks in advance for any info or references!

Thomas
Back to top
View user's profile Send private message
rene



Joined: 17 Mar 2005
Posts: 125

PostPosted: Wed Jun 21, 2006 9:05 am    Post subject: Reply with quote

I've found the brightness uneven between images, 'flickering' and was told that this was because of the 50Hz cycling of the lamp. Further then that, ok.

Rene.
Back to top
View user's profile Send private message
Thomas Ashcraft



Joined: 31 May 2006
Posts: 25

PostPosted: Wed Jun 21, 2006 10:15 am    Post subject: Reply with quote

Rene wrote: "I've found the brightness uneven between images, 'flickering' and was told that this was because of the 50Hz cycling of the lamp. Further then that, ok."

Rene,

What camera model have you used?

I can see that there could be a conflict with a frame per second rate and illuminator/rheostat flicker.

I am going to try and collect data on this subject as I have not seen much written so far.

Thanks.
Thomas
Back to top
View user's profile Send private message
rjlittlefield



Joined: 06 May 2005
Posts: 727
Location: Richland, WA, USA

PostPosted: Wed Jun 21, 2006 2:00 pm    Post subject: Reply with quote

Possibly relevant info...

I have encountered problems with line-frequency flicker. Especially with fluorescent lighting, there's a periodic cycling of brightness & color balance as the line power drifts in and out of sync with the video frames.

However, I recently purchased a midrange fiber optic illuminator (like eBay item 7631755942) and was pleasantly surprised to find that it's using some sort of high frequency switching power supply that delivers 36KHz AC to the halogen bulb. There's no significant ripple in the light at that frequency, due to thermal inertia of the filament.

I didn't quite trust the electrical meter, so I also ran a short series of exposures at 1/1000 second, and confirmed no difference in brightness between frames with random timing.

I don't know if this high frequency switching is common to other fiber illuminators, but if you're lucky enough to get it, you shouldn't have any flicker problems.

--Rik
_________________
Reworks and reposts of my images in this forum are always welcome, as are constructive critiques.
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
This forum is locked: you cannot post, reply to, or edit topics.   This topic is locked: you cannot edit posts or make replies.     Forum Index -> Macro and Micro Technique and Technical Discussions All times are GMT - 7 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB 2.0.6 © 2001, 2002 phpBB Group