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EVF and "Double Vision" - Is there a link???


graeme_clarke

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After the best part of a week in South Africa photographing wildlife with a Sony A7R and Leica 280 + 2x converter lenses, I developed vertical double vision. I'd concentrated hard on focusing on the subject and often used the viewfinder 10x facility used to get a sharp picture - which took a lot of time and care when using the 280 and 2x combined. I'd taken about 2000 images

 

On returning to the UK at the beginning of March, tests run by the doctor (CT scan, blood tests) and optometrist all are normal. It's only now that vision is returning to normal when looking straight ahead or to the right. Looking left is still blurred. Some kind of strained muscle may be the cause.

 

My question is this - has anyone else experienced similar difficulties when using a camera with an EVF? Is there likely to be a link between extended use of an EVF this way and some kind of eyestrain in one eye compared to the other (either one of the oblique muscles that move one eye, or ciliary muscles in one eye) that can lead to double vision for a couple of weeks or so?

 

I'd very much value your comments.

 

Best wishes,

 

Graeme

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Just having had a lens implant and cornea transplant in my (non-shooting:)) left eye, I am quite alert to this kind of questions. My doctor assured me that using the eye, no matter which way, including computer screens etc. could not possibly influence the physical healing process.

I rather suspect that heat and low moisture content of the air could have led to dehydration and subsequent deformation of the cornea, especially if you are pressing your eye to the EVF which will have prevented blinking.

Edited by jaapv
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I have not experienced difficulties... but I do have the precise feeling that usage of the EVF, and so much if accompanied with the magnification (and you say you often used it) IS definitely a stress for eye ; I have too little experience now, and only with M accessory, and haven't idea about the muscles impacted by this stress... but I think that the combination of refresh rate of LCD and small movements amplificated by magnification is not a benefit for eye; EVFs are a relatively new technology.... and maybe there isn't yet a clinical history and literature about, but wouldn't be surprised if something on the matter has been or will be written in some professional publication.

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Thousnads of pictures each in hot, humid Panama and Indonesia, each for two weeks and one week with thousands of picutures in warm, dry central Mexico within one year using an EVF had no such impact on me.

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Well, yes, the same for me with six yearly weeks in dry and hot Africa,and last year 14 days of intensive EVF shooting in similar conditins as Graeme, but the OP is clearly seeking an explanation.

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Perhaps using the long telephoto may have caused some eye strain because of the image movement in the viewfinder? I think an EVF can be tiring with an un-stabilised image especially as the long lens exaggerates tiny movements of the camera. It isn't like the old days of using a split image to focus a telephoto, the modern EVF promotes critical focusing which isn't always nice (but is still necessary) if the camera is moving. I have never found an EVF to be tiring on a camera with image stabilisation using a telephoto or using wider angle lenses on an un-stabilised camera which even with focus magnification don't jump around as wildly.

 

Steve

Edited by 250swb
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The M EVF works best - and is more stable at 5x with long teles, which makes for a calmer image. It is very precise in the circumstances described. The Sony EVF is more "inyour face" which invites use at 10x making it very unstable.

 

A tip for focusing Safari photography: Don't focus on the animal itself. Unless you happen to have a strong contour in exactly the right place, getting focus on fur is extremely difficult. Focusing on branches or grass just beside the animal is much easier. You can "walk" the plane of focus forwards and backwards and position it extremely precisely.

Edited by jaapv
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... I'd concentrated hard on focusing on the subject....

 

Graeme--just a wild thought: When concentrating on the subject, did you possibly squint your non-shooting eye? Perhaps the problem is with that eye? That was a problem some people had some years ago, before the advent of autofocus.

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Thanks for your replies folks,

 

I too at first thought dehydration was the cause - I'd been on another reserve, then driven back in a Range Rover (very nice car) for about an hour and it was only after I got out that the vertical double vision became apparent. It seemed to happen suddenly and was not obvious whilst in the car. But after a large drink of water and tea, then a lie down, it was no better.

 

Once I got home my optician found nothing wrong optically with each eye and suspected a circulation issue as the cause - said a CT scan may not show one - and blood electrolytes and sugar levels are within norms. in his experience the phenomenon usually clears up in 4-6 weeks. The problem was obvious for the first week after returning to the UK, and has improved daily since then.

 

It's certainly true that the image from a 560mm equivalent at 10x magnification dances around - image stabilisation would be a godsend! So, thanks for your advice on focusing Jaap - I had been trying for nice sharp eyes - on animals that never keep quite still. I'll give it a go if I get a chance next year - Mrs C is having a lot to say about that at the moment...

 

More anon,

 

Graeme

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Next tip: Use a beanbag. It is the best stabilization you could wish for. A tripod on safari is useless, unless you are in a hide, and even then a beanbag is preferable in most cases. When walking, use a tree branch and/or a monopod/walking stick.

 

Greame, do look beyond South Africa. If you want some ammunition to convince your wife, shoot me a PM with her preferences and I’ll give you a few tips.

Edited by jaapv
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Thanks Jaap,

 

Good advice about shooting aids - most of the time I used a monopod, occasionally a beanbag - and I'd advise anyone else to take the same equipment. I took a tripod and, apart from some macro work with the DMR and a 100mm, it was surplus baggage!

 

Best wishes,

 

Graeme

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Graeme -

 

Jaap has a great deal of experience on safari in many African nations and I storngly urge you to take him up on his offer. Additionally, you might want to check my site for Barbara's trip notes and my photos of several African nations.

 

I also agree with Japp about the bean bag. If your tour operator doesn't provide them you can bring an empty zippered canvas bag in your luggage and fill it with pebbles or sand when you arrive at a Safari camp.

 

Regarding the ride back in the Range Rover. By chance was the air conditioning on and blowing towards your face? If so I wonder if that might have had a dehydrating impact on your eyes.

 

Howard's thought strikes me as possible too. I've never had the double vision issue you describe, but I always keep both eyes open when shooting.

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Actually the silliest thing on the market are the "safari"clamps RRS are marketing to make a kind of swinging support for use in a safari vehicle. They are not only guaranteed to hit the person sitting in the seat before you around the head, they will also transmit all vibrations and movements of the vehicle and fellow passengers to your camera. And the Landrover has springs, such as they are. Fancy a tripod on springs?:D

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I had the same problem back some years ago when I photographed track and field events with a Nikon F3 and a 50-300mm Nikkor. I absolutely loved that lens, but took a lot of concentration to focus perfectly. It could take 24 hours for my vision to come back.

 

There is a definitive cure. For me it is a Nikon D2x and auto-focus lenses. I shoot auto racing all weekend with no eye strain, very fast operation and nearly 95% correct focus. (Time for a D4s for much improved autofocus.) I love my Leicas, but there are times where 21st century technology is the answer. Why risk your vision and deal with the frustration of unstable 10x pixel peeping? Enjoy long telephoto photography.

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After a series of blood tests, a CT scan and rigorous eye examinations today the ophthalmologist has answered my original question. She believes I suffered a problem with an artery serving the muscle/nerve that moves one eye and is pleased it has recovered quickly (apparently a week to 10 days is quick) though there is still a little double vision at the extreme "upper corners". She suggests it is more likely a constriction of an artery serving the nerve/muscle controlling an eyeball movement rather than a blockage inside the vessel. An event she believes coincidentally happened whilst I was in South Africa and is nothing to do with using a camera - so good news in both respects. One of those things that can happen as we get older?

 

Best wishes,

 

Graeme

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After a series of blood tests, a CT scan and rigorous eye examinations today the ophthalmologist has answered my original question. She believes I suffered a problem with an artery serving the muscle/nerve that moves one eye and is pleased it has recovered quickly (apparently a week to 10 days is quick) though there is still a little double vision at the extreme "upper corners". She suggests it is more likely a constriction of an artery serving the nerve/muscle controlling an eyeball movement rather than a blockage inside the vessel. An event she believes coincidentally happened whilst I was in South Africa and is nothing to do with using a camera - so good news in both respects. One of those things that can happen as we get older?

 

Best wishes,

 

Graeme

 

This makes sense. Diplopia (double vision) is caused by ones 2 eyes pointing in 2 different directions. It is caused by weakness of at least one of the extra ocular muscles (there are 6 for each eye). Vertical diplopia would be caused by weakness of either the superior rectus or inferior rectus muscles. The cause of this could be neurological, vascular or less commonly mechanical damage. It is not caused by environmental conditions like dryness or dust, which could affect the cornea or conjunctiva. Diplopia is quite distressing, I'm glad you are improving Graeme.

 

Roy

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