Unexpected stripe

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All Ex
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Joined: Mon Jul 20, 2015 3:54 am
Location: Greece Thessaloniki

Unexpected stripe

Post by All Ex »

Just when I've found a way to decent light in my photos, a strange behavior appeared on this one:

Image
D800E continuous lighting, 25th of a sec,ISO 100,Mitutoyo 5X, tube lens based on the Raynox 150 DCR as Rik posted, PMax, 168 staks

I know that it's a little bit underexposed, I also had to work a little bit my step size but as you can see it is not what bothers me in this case.

I project my stacks on my 39 inches TV, it`s the first time that this appears.
What do you think is causing it?
All--Ex
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rjlittlefield
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Post by rjlittlefield »

What type of lighting are you using?

--Rik

All Ex
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Post by All Ex »

I`ve formed a 3 LED`s of 10W each (in parallel connection) :

Image

In Fact, I`m planning, after testing it to submit a post here.
All--Ex
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rjlittlefield
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Post by rjlittlefield »

The horizontal banding that you show is typical of what happens with lights that flicker at the mains frequency, combined with a shutter speed that is very similar to that. With an LED system, this will be determined by the nature of the power supply.

--Rik

All Ex
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Post by All Ex »

Lots of the thinks a handicap should do, at least I`m now finished for the present hour (as I`m saying: being a handicap is a fool time job, thus we are doing procedures throughout the day) anyway, this formation works with 12 V 3.5 A and I power it with a 12V, 6A and a 47W power supply. For a solution, I`m thinking (a former solution I made) to add a pair of a 7W LEDs with equal sufficient power supply.
Just to provide me enough light in order to reduce the shutter speed, do you think this would solve my problem?
All--Ex
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lonepal
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Post by lonepal »

Hi;

I think you need a high quality flicker free psu for LEDs or some anti flicker resistors.

https://www.instyleled.co.uk/what-cause ... happening/
Regards.
Omer

All Ex
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Joined: Mon Jul 20, 2015 3:54 am
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Post by All Ex »

I`m copying his suggestions:

1. Always drive LED products using an LED power supply that’s designed for the job. Don’t use any LED strips that are driven by mains AC!
2. Make sure all your LED products are compatible with the control circuits and power supply you’re using.
3. Check for loose wiring and other faulty connections. And make sure your LED dimmers are not overloaded.
4. Consider using a constant-current LED driver.
5. When installing a dimming system, experiment to see if there’s a minimum dimming level that you shouldn’t go below.
6. For dimming systems, consider using a zero-to-10V or digital volt-dimming system rather than a TRIAC alternative.


dimming is not applied in my case
I obviously used an appropriate for LEDs power suply

I couldn`t figure out how can anybody decide whether his LEDs are compatible with the control circuits and power supply he is using.
Although he/she in some place says that dimmer and controller have the same meaning, in another segment of his text I presumed that if you provide plenty of power in the current you use this can help somehow to overcome the issue.
There I come to my initial proposal, once again I think that if the shutter speed should be enough fast the problem must be overcome.
(it is obvious that I`m using power supplies way beyond the needs of the systems)
All--Ex
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lonepal
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Post by lonepal »

Regards.
Omer

All Ex
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Joined: Mon Jul 20, 2015 3:54 am
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Post by All Ex »

lonepal thank`s for the link, I`ll try my other solution and after a discussion with a friend of mine who is in electronics, I`ll see what I`ll do.

:wink:
All--Ex
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