flash photography harming T eyes?

prey

Arachnosquire
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Someone was posting a side-thought on the blacklight thread about hi-watt ones possibly harming invert's eyes (or not) and it made me think about when we photograph these non-iris posessing (not having a variable aperture), nocturnal little beasts with over-zealous flash on macro. Has anyone ever tested T's sensitivity to light before and after ample flash exposure? How would we know without careful testing if it blinded them? A captive, blind T would probably seem normal due to its reliance on vibration, usually.
:?
I'm not saying I really think it does. Their eyes would have to be particularly delicate due to not being made for extremes or something. My iris doesn't have time to effectively respond to a flash, anyway, when I'm partying in the dark and a flash goes off. In the mood lighting. In my van. Down by the proverbial river. A creek, actually.
Ok, it's sort of a ditch, but I prefer the term "estuary" during flood season.
 
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starmaiden

Arachnosquire
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That is a good question. Just for safety's sake and in consideration of the critter, I try to stand back at least a few feet when photographing all my critters and use the zoom lens. It works with the macro too. FWIW, it doesn't seem to bother my hermit crabs, which are nocturnal, non-iris, nonblinking organisms. :?
 

rYe

Arachnosquire
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I've thought about this myself, if most T's eyes can only tell the difference betwwen day and night the flash must be serious problem. I've yet to take a pic of my T's because of this, I just don't see how a spider could handle a sudden flash of extreme light!
 

Cockroach_PL

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I don't think so... I took a lot of pictures of my T's, and they never react (what, IMO, they would do if it is harmful) when the camera flashes.
Spiders have eyes, but they rather not use them. Spider can only see whether something is dark or light, so it doesn't use it for example for hunting. Other sences are far more important than sight.
 

Cirith Ungol

Ministry of Fluffy Bunnies
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One aspect of it is also that there are quite many individual T's that end up in bright sunlight, for example males. With eyes all arround they can't avoid "looking" at the sun. So in my mind that is a sign that they might not be as bothered by bright light as we think. At least not to a point where it hurts them in any way.
 

SPIDERBYTE

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The fact that the eye lenses are so small probably limits some of the hazards of being blinded by walking in the sunlight. If the lenses were any larger, they might act like a magnifying glass and bake the inside of the eyes. I wonder how those little jumping spiders cope, they have the biggest eyes for their tiny body size, do they have to avoid the sun? Next would be the arboreal T's like Avics, well I guess they would normally be under the tree canopy, so they wouldn't get full sunlight in the eyes.

I still try very hard not to use the flash, even though the flash pulse is extremely short and probably doesn't last long enough to overheat the inside of the eyes, still I wont use it anyway to avoid startling the T. I have had the flash accidentally go off, and the T stayed still -- dont know if it cant see such a short pulse, or the nervous system cant process it, or if the T just doesn't care (still, I wouldn't want to make it "think" that it was in a lightning storm)
 

brachymad

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I have taken thousands of photographs using a macro flash mounted on the end of the camera lens. I have never seen a T react in any way to the flash. I would have thought if it caused it any sort of distress I woud have seen at least a bit of reaction from some of them.
 

prey

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I, too, noticed T's don't noticably react to flash. So, unless it's just overloading their circuits, or they're like the proverbial deer in headlights, it's one sign suggesting the stress may be on the low end. Then again, *I* might not immediately react to (or even notice) 1/100 second of personal exposure to some forms of serious radiation, though detrimental consequences may very well occur.
Another thing is that spiders can't rotate their eyes away from the sun if they're unexpectedly forced to shoot out into broad daylight, which I would think happens to evolutionary significant numbers of wild T's sometime during their lives. They probably wouldn't be physiologically "designed" to have their peepers instantaneously flame-broiled by darting into direct, high-noon photonic intensity for 100's of percents longer than the duration of any modern flash.
But I just don't know if there's a conclusion to this unless a lab environment is set up with immaculately isolated stimuli, etc. and tests are done. Some specimens, who markedly react to mere movement of light, could be flashed and then tested again for the same behavior. But it can't be me anytime soon :)
 
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SPIDERBYTE

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I rember following a link from this board to an article about T vision, the experiment was on a basically "decapitated" :eek: T carapace in some "spider saline" solution, with electrodes hooked up to the optic nerve output. The signal would diminish after initial light exposure (something like the "auto exposure" on a digital camera I guess)

There was also graphs of where the peak light wavelength responses are.
 

prey

Arachnosquire
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Interesting, and thanks!

You know, I was thinking: what about trying cheap, sheet gel filter lighting material, used in front of the flash to, not only cut the T's overall blast exposure, but also bring out the best colors from the get go. Different gels for different T's. I've used this concept in a reverse fashion for amatuer astronomy.
:)
 

stk5m

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just a thought

spiders in general have been around for millions of years longer than we have and have survived many lightning storms without going extinct. i don't think a flash from a camera would harm a t.

just my 2 cents
 

guitarlust

Arachnosquire
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that's a good question to ponder. especially when getting photos of the spider molting. i have wondered that as the flash is going off and if i am causing damage to the eyes of a spider who has not had time for the exoskeleton to harden. then i am aware that they do not use the eyes as a source of information input as much as they do the sense of touch.

on a side note, how good is the vision of a spider eye? i placed my g. rosea's (frohike) enclosure in front of a mirror in changing my furniture around in the room and as soon as it looked into the mirror it stopped and was waving its leg around like it was waving to the spider in the mirror. i know it was probably for some other reason, but it seemed odd as to the behavior and given the fact it was looking into a mirror.
 

Derek W.

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on a side note, how good is the vision of a spider eye?
I don't think anyone knows for sure. Many people seem to think that they can only really distinguish between light and dark. But that doesn't necessarily make sense when you think about aboreal T's because they have to navigate tree branches, and sometimes jump to a different branch. Then when you really think about it even that isn't a solid arguement that their eyesight might be better than most people think because we are looking at it through our human point of view. We really don't know to what extent their other senses can operate like our vision, and to go even further our eyesight isnt even that great, nor is any other sense we have. For all we know we could be the blind ones compared to the senses a T has.
 

prey

Arachnosquire
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The above post hints to things I'm thinking about when one says their T responded to a mirror (posted just before that). Those primitive eyes could be programmed to identify specific (though limited) patterns of rough shape and movement, such as an engram specific to shadowey T front leg gesticulation.
 

DrAce

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Insect Vision (maybe Spider too?)

This post will wander off topic, but will get back there, I promise!

I recall going to one of the best seminars I have ever experienced at my university last year. It was an Australian researcher who was looking at flying insects, and how they respond to sight - particularly navigation in bees and wasps, but also ants etc.

His data revealed that insects judge distance and speed using the same relative mechanism. Basically, they look for repetative objects (like trees, or leaves or something in their environment) and then watch how fast they go past. Think travelling in a car - the trees next to the road go past quick, but the mountains and sun only change slightly in relation. If you artficially make near objects go past slowly, then they list off to the side - and eventually crash if they meet a wall.

Fundimentally, a spider eye is constructed differently to an insect, but they may well navigate in a similar way. The reflection may have been observed, and lead the spider to see something moving 'quickly' in relation to itself. Just a hypothesis that might explain a strange behavior. See if it responds similarly to a moving object behind glass (the glass should remove any possible vibration).

In terms of flash exposure, I don't think any long-term damage is done with a flash. Damage to retinol in the eye normally comes about through long-term exposure, not short flashes. There are lots of mechanisms in the biochemical world to cope with short term exposure. Radiation, or oxygen exposure, poisoning, etc. Normally, a short acute dose of any of these will not cause long-term damage, because there are good mechanisms for the repair of this damage (free-radical sinks in the case of radiation and oxygen, and the liver for most poisoning - using P450 type of enzymes, or the kidneys to flush out poisons). Spiders almost certainly will have the same mechanisms.

Light tends to cause oxidative stresses to pigments - it knocks electrons out of some molecules and leads to breakdown of various proteins and DNA... but the eye in particular has good mechanisms for responding to those stresses. I think that short-term flashes shouldn't do long-term damage, but may 'blind' the spiders for brief spells, in the same way it does us.

The 'lightning' example given earlier is not really comparable. A camera flash gives a much higher dose of light than a lightning flash does.
 

phil jones

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i will not use flash photos now as when i did on a big t- BLONDI 8ins leg span it was acting strange for about 4 days after a coincidence ? i just do not know so no to the flash :? :confused: :embarrassed: :embarrassed: === phil
 

DrAce

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Was it JUST a flash photography session, or were you manipulating the spider as well? If it was moved or disturbed, could this have been responsible for the altered behavior. Also, how many flash photographs did you take? Are we talking a one-off, or several?

DrAce
 

phil jones

Arachnoprince
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Was it JUST a flash photography session, or were you manipulating the spider as well? If it was moved or disturbed, could this have been responsible for the altered behavior. Also, how many flash photographs did you take? Are we talking a one-off, or several?

DrAce
3 picts of it in its tank i did NOT move it ?
 

DrAce

Arachnodemon
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So, do an experiment

So, here's the nex thing to do. If you know your spider reacted that way once, try it again.

If the same result is seen, then you can be relatively sure that it's the flash.

Perhaps you may want to see if the number of flashes is significant, so try with a few less 'flashes'.
 

Nerri1029

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I would have to add that while intensity is a factor the wavelength is probably more important.

If you are worried get a tripod and use ambiant.

honestly I am not worried about this.

Duration and intensity "seems" unlikely to do any perm harm.
 
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