www.photomacrography.net :: View topic - Flash: prevent overheating, no flash: avoid motion blur?
www.photomacrography.net Forum Index
An online community dedicated to the practices of photomacrography, close-up and macro photography, and photomicrography.
Photomacrography Front Page Amateurmicrography Front Page
Old Forums/Galleries
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Flash: prevent overheating, no flash: avoid motion blur?
Goto page 1, 2  Next
 
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Macro and Micro Technique and Technical Discussions
View previous topic :: View next topic  
Author Message
nielsgeode



Joined: 31 Jul 2012
Posts: 246
Location: Groningen, Netherlands

PostPosted: Tue Feb 17, 2015 1:47 am    Post subject: Flash: prevent overheating, no flash: avoid motion blur? Reply with quote

Recently, I have changed my exposure approach and I am now a fan of Exposure to the right (ETTR). It works briliantly in reducing noise in the darker areas of the image and I can strongly recommend using it *if you shoot in raw*

However, there is a price to pay: a lot more flash power: 2 to 4 stops more
It happens now quite often that (at 10 - 20 x mag) I need 1/1 or 1/2 for 300 to 600 frams with my speedlite 600 EX flashes. They don't like that Crying or Very sad and stacking takes me hours

I have also looked into changing from flash to IKEA LED's. I did a small test: four IKEA led's that illuminate my subject (small group of Lindbergite crsytals) with a piece of paper as diffusor. I have filmed the static live view and you can clearly see that nothing stops moving:
http://nl.tinypic.com/player.php?v=mcdrtx&s=8
This is a bit of a problem with a 30 seconds exposure time.
My setup consists of a steel baseplate with three large sorbothane spheres under the plate.

How can you reduce vibrations even more?
How do you do exposure with continuous light and how do you avoid motion blur?
If you use flash, how do you prevent overheating?
There is also the Nissin MG8000 which, according to the manufacturer can fire a 1,000 flashes continuously without overheating: http://www.nissindigital.com/mg8000.html
Is there any experience with this flash in stacks? How does it perform and would you recommend it?

Thanx,
Niels
Back to top
View user's profile Send private message MSN Messenger
Charles Krebs



Joined: 01 Aug 2006
Posts: 5800
Location: Issaquah, WA USA

PostPosted: Tue Feb 17, 2015 3:06 pm    Post subject: Reply with quote

Quote:
This is a bit of a problem with a 30 seconds exposure time.


The Ikea lights are not extremely bright, but typically very adequate for 10X and 20X objectives. A thirty second exposure time seems far too long for these magnifications. Something doesn't sound right... (diffusion too dense?, lights too distant?)

Perhaps a quick photo of your set-up might provide a clue as to why your exposures are so long. Also, what optics are being used?

In any event, you will need to track down the source of the movement that is seen in the video you linked to. Any idea what might be causing it?
(I'll occasionally check my magnified live view and it is rock steady... as long as no one is running around upstairs or the clothes dryer is not tumbling Wink )
_________________
http://www.krebsmicro.com
Back to top
View user's profile Send private message Visit poster's website
DQE



Joined: 08 Jul 2008
Posts: 1653
Location: near Portland, Maine, USA

PostPosted: Tue Feb 17, 2015 3:10 pm    Post subject: Reply with quote

There are professional grade flash units that allegedly will not overheat. Wedding photographers use them too.

A brand that I have some familiarity with is the Quantum brand. I've used their external auxiliary flash batteries with no issues for several years, with good performance.

Here's a link to one of their models:

http://www.qtm.com/index.php/products/qflash/trio-shoe-mounted-flash

"TRIOs never can be driven too hard. Fire them at full power as fast as possible for as long as you need to. Trio light output exceeds that of typical shoe-mount and handle-mount flashes, especially for bounce lighting."

The high output and short exposure duration of a conventional flash unit has advantages for reducing image blur due to camera and/or subject vibration.
_________________
-Phil

"Diffraction never sleeps"
Back to top
View user's profile Send private message
Peter De Smidt



Joined: 05 Jan 2012
Posts: 233

PostPosted: Tue Feb 17, 2015 3:19 pm    Post subject: Reply with quote

Godox bare bulb flashes, and the re-branded versions of these, are worth checking into. They are very resistant to over heading, and the lithium batteries are terrific. In addition, they are very easy to set. Adorama, Cheetahstand, and many others relabel these flashes. I have three of them that I use for commercial shoots. Any of these is going to be much bulkier than the Ikea lights.
_________________
www.peterdesmidt.com/blog


Last edited by Peter De Smidt on Tue Feb 17, 2015 8:33 pm; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 2979
Location: Ohio, USA

PostPosted: Tue Feb 17, 2015 4:02 pm    Post subject: Reply with quote

Quote:
My setup consists of a steel baseplate with three large sorbothane spheres under the plate.

A photo of your setup might also help us understand the movement shown in your video. In your video, it appears that the resonant frequency of the motion is pretty high--which makes me suspect that your Sorbothane spheres are too large or too dense for the mass of your rig. As you may be aware, you need to match the squishiness of the elastomer feet to the needs of your rig and environment. My sense is that you need softer feet--but that's a stretch, not knowing more about your situation. And it may not be the only issue.

--Chris
Back to top
View user's profile Send private message Send e-mail
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 7689
Location: Near London, UK

PostPosted: Tue Feb 17, 2015 5:14 pm    Post subject: Reply with quote

Peter - is that Godox?
Back to top
View user's profile Send private message
Peter De Smidt



Joined: 05 Jan 2012
Posts: 233

PostPosted: Tue Feb 17, 2015 7:49 pm    Post subject: Reply with quote

Yes. Sorry about that.

Here's a link to a reseller:
https://www.cheetahstand.com/A-New-Bare-Bulb-Flash-Arrives-p/cl-180pcombo.htm

With regular speedlights, the flash tube is in the main plastic housing. When the tube is fired, it heats up, and if this is done enough, the housing, and the stuff in it, can start to melt. One way to deal with this is to make the flash lower it's power after many flashes or increase the delay between flashes.

With barebulb speedlights, the flashtube is not contained withing the plastic body of the flash, and so it's much less likely to cause heat related damage.

If that's not enough, you can switch to studio strobes, which are usually bare bulb, metal, and have cooling fans. They're likely to be too strong for macro needs, especially the older units, and they're bulky. Digital cameras tend to be more sensitive to light than film cameras. I did a test last week in studio. One was with my D600 at EI 100. The other was with a Fuji Gx680 with Fuji Acros rated at an EI of 80. The D600 had at least 1 stop more shadow detail than the film exposure.
_________________
www.peterdesmidt.com/blog
Back to top
View user's profile Send private message Visit poster's website
nielsgeode



Joined: 31 Jul 2012
Posts: 246
Location: Groningen, Netherlands

PostPosted: Wed Feb 18, 2015 12:31 am    Post subject: Reply with quote

DQE wrote:
There are professional grade flash units that allegedly will not overheat. Wedding photographers use them too.

A brand that I have some familiarity with is the Quantum brand. I've used their external auxiliary flash batteries with no issues for several years, with good performance.

Here's a link to one of their models:

http://www.qtm.com/index.php/products/qflash/trio-shoe-mounted-flash

"TRIOs never can be driven too hard. Fire them at full power as fast as possible for as long as you need to. Trio light output exceeds that of typical shoe-mount and handle-mount flashes, especially for bounce lighting."

The high output and short exposure duration of a conventional flash unit has advantages for reducing image blur due to camera and/or subject vibration.


wow they look really nice Cool
but....wow they are expensive Shocked For this amount of money you can buy a professional 900W monolight
Back to top
View user's profile Send private message MSN Messenger
nielsgeode



Joined: 31 Jul 2012
Posts: 246
Location: Groningen, Netherlands

PostPosted: Wed Feb 18, 2015 1:25 am    Post subject: Reply with quote

Charles Krebs wrote:
Quote:
This is a bit of a problem with a 30 seconds exposure time.


The Ikea lights are not extremely bright, but typically very adequate for 10X and 20X objectives. A thirty second exposure time seems far too long for these magnifications. Something doesn't sound right... (diffusion too dense?, lights too distant?)

Perhaps a quick photo of your set-up might provide a clue as to why your exposures are so long. Also, what optics are being used?

In any event, you will need to track down the source of the movement that is seen in the video you linked to. Any idea what might be causing it?
(I'll occasionally check my magnified live view and it is rock steady... as long as no one is running around upstairs or the clothes dryer is not tumbling Wink )


I have no clue what is causing the movement Crying or Very sad This weekend, when I have more time available I will do some experiments to see if I its everywhere in the house.

I use a Canon 5D III + 200 f/2.8 L II + Mitu 10x NA 0.28 (altough I also have the 5x, 7.5x, 20x and 50x Mitu's)

Also: do not forget that I want to expuse using ETTR. In this stack for instance, I need to 'recover' the exposure by -3 stops in the raw conversion. This gives much better results than the 'correct' expsoure.

To illustrate, just a single image (that's why its mostly blur or bokeh) from a stack I am running at the moment (using flashes). Shown are two jpg's created from the same raw with and without exposure compensation in the conversion:

http://i62.tinypic.com/15p4mqu.jpg
http://i61.tinypic.com/2mrh1c8.jpg

And here are some photos of my current setup:

http://i58.tinypic.com/2wpm79h.jpg
http://i57.tinypic.com/2093y9h.jpg
http://i62.tinypic.com/28cqbec.jpg

I use a large sheet of polarizing film and a piece of paper between my flashes and the subject. I used to have a polarizer between my 200 f/2.8 and the Mitu, but I removed it and switched to polarizing the flash light instead.

Suggestions and comments are welcome Very Happy
Thanx
Niels
Back to top
View user's profile Send private message MSN Messenger
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 7689
Location: Near London, UK

PostPosted: Wed Feb 18, 2015 3:47 am    Post subject: Reply with quote

I suspect you could do better with a more rigid connection between the camera and subject. You have a lot of "height" there. In live view, if you touch things lightly it can be possible to see which parts are less damped.

I've not used one on a photo rig but a tire/tyre inner tube can provide a good cheap vibration isolator - "tune" by pressure.
Back to top
View user's profile Send private message
nielsgeode



Joined: 31 Jul 2012
Posts: 246
Location: Groningen, Netherlands

PostPosted: Wed Feb 18, 2015 3:57 am    Post subject: Reply with quote

ChrisR wrote:
I suspect you could do better with a more rigid connection between the camera and subject. You have a lot of "height" there. In live view, if you touch things lightly it can be possible to see which parts are less damped.

I've not used one on a photo rig but a tire/tyre inner tube can provide a good cheap vibration isolator - "tune" by pressure.


I have quite some height indeed. I have a horizontal setup where my camera is fixed during stacking. Since I also stack crystals and my specimens can vary a lot in height I have choosen this setup for flexibility, so I can easily accomodate small crystals or insects as wel as larger specimens that contain tiny crystals.

Only the subject moves on the stackshot moves.

I think I don't completely understand what you mean by more rigid connection between the camera and subject. Could you please make that a bit more clear to me?
Back to top
View user's profile Send private message MSN Messenger
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 7689
Location: Near London, UK

PostPosted: Wed Feb 18, 2015 4:41 am    Post subject: Reply with quote

I mean -
imagine two coil springs fixed at one end of each, to the table.
Put the camera on top of one, and the subject on top of the other.
Camera and subject can move about independently.

Now put a rigid iron bar (dotted) between the tops of the springs. Camera + subject can still move relative to the table, but not much relative to each other.

If the springs are strong, then movement in the floor gets transmitted to the bar relatively well.
If the springs are weak, it's better for isolation.
If the bar is a higher mass, that's better too, because more energy has to be transmitted to move the bar about, more so at high frequency.

As the mass goes up and the spring strength(stiffness) down, the frequency of the vibration you can transmit from floor to bar goes down. Below a frequency you could calculate if you knew the numbers, more of the movement in the floor starts to get transmitted to the bar. So you want that frequency to be lower than whatever you care about.

The bar increases the transmission of vibrations directly between the camera and subject. Hopefully (using EFSC) those are too small to notice. As magnification goes up, they may not be, so the bar would make things worse. (Hence, people separate cameras from microscopes.)

In your situation you have Sorbothane feet, which are also springs, (though well damped) which makes a two-stage arrangement, but the same principles apply. As Chris S says, they may be transmitting high frequencies too well (too small/stiff) so the camera and subject move about separately.

Back to top
View user's profile Send private message
nielsgeode



Joined: 31 Jul 2012
Posts: 246
Location: Groningen, Netherlands

PostPosted: Wed Feb 18, 2015 5:14 am    Post subject: Reply with quote

Quote:
In your situation you have Sorbothane feet, which are also springs, (though well damped) which makes a two-stage arrangement, but the same principles apply. As Chris S says, they may be transmitting high frequencies too well (too small/stiff) so the camera and subject move about separately.


Thanx, it makes a lot clear. What do you mean by a two-stage arrangement? I have the sorbothan feet under a the entire setup. So my camera and my subject are support by the same (three) sorbotane feet.
Back to top
View user's profile Send private message MSN Messenger
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 7689
Location: Near London, UK

PostPosted: Wed Feb 18, 2015 6:19 am    Post subject: Reply with quote

two-stage:
You have "springiness" in both the Sorbothane feet and the metal supports for the camera.subject.
They will transmit vibrations differently.

The metal supports will not be well damped, so if they are set moving by whatever gets through the Sorbothane, they will tend to keep moving, and separately from each other.
If the supports were shorter (ie less high), the camera and subject would move less because 1) the supports would be stiffer and 2) the radius for any angular movement would be shorter.
Back to top
View user's profile Send private message
xavosp



Joined: 20 Apr 2013
Posts: 23
Location: Spain

PostPosted: Wed Feb 18, 2015 8:08 am    Post subject: Reply with quote

You may also try adding another layer to your base, bellow the sorbotane feet, but as you already are using steel and wood, I would try a different material, such as granite or concrete.

Different material usually means it will damp a different range of vibration frequencies.

Then you may add a few more sorbothane feet under that new layer, or an tyre inner tube, as ChrisR suggested.

I'm using a tyre inner tube in my rig, and it works wonderfully well to me. Nevertheless you should be aware that it will feel quite unstable while positioning the specimen, changing lenses, and anything that means touching the rig.

On the other hand, I would bet for a better/stiffer connection between the camera and those stages. I think that lens collar is suspiciously prone to induce swinging to the camera
_________________
Xavier
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Macro and Micro Technique and Technical Discussions All times are GMT - 7 Hours
Goto page 1, 2  Next
Page 1 of 2

 
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 © 2001, 2005 phpBB Group