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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

After the FL: 7 years with a Zeiss Victory HT 8x42 (2 Viewers)

Troubador

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After the FL came something very different indeed: the HT. To me it looked classically and classily elegant, and its forward-placed focus wheel allowed three fingers of my right hand to grip the tube, with my first finger falling naturally on the focus wheel, so in hindsight it was nearly an open bridge grip, without the bridge at the objectives. And yet the HT wore its two bridges, one above the focus wheel and one below, not just openly, but with them emphasised by a surrounding framework, so they became a prominent feature. I loved it and loved the way it took the FL view to the next level of transparency with, IMHO, just a touch more red in the colour balance.

Choosing memories from my time with the HT has been really difficult because luck seemed to be with us and provided so many first-class sightings. OK, let’s start.

On the tip of the Ardnamurchan Peninsula, in late autumn, we found a wintering Slavonian Grebe. You might say there was nothing earth-shattering about this, but what was utterly surprising was this individual repeated swam within 5-6 metres of us as we sat on the rocks watching it. Time and again it slowly circled our small bay, diving and surfacing and eventually passing close to us again. What a beautiful bird, even in winter plumage. And yet this wasn’t the first Slavonian to have come so close to us. Way back in the 1970s as we hid beneath a big old willow tree to answer ‘calls of nature’ a Slavonian Grebe, in full breeding plumage, came swimming through the willow fronds so close to us we could almost reach out and touch it. It took one look at us as we (ahem) adjusted our dress, and carried on its way, through the willow fronds at the other side and disappeared. From its demeanour one might have deduced its motto was ‘keep calm and carry on’ as it swam steadily by without missing a beat. Slavonian Grebes are cool dudes.

In spring the following year another water-bird captured our hearts. This time it was a female Goosander, swimming close to us with a crew of chicks on her back, in the channel between the Scottish mainland and the Isle of Skye. We had chosen to travel over to Skye on the one remaining small ferry (the ‘Glenachulish’, Kylerhea ferry) rather than take the big ship ferry or the bridge, and this lovely Goosander was ample compensation for the extra time and mileage, plus we glimpsed an Otter in the distance from the Glenachulish.

Little did we know at this point that we were destined to see far bigger species, and in abundance, later in this during this visit. On the journey back from the Western Isles, we stayed on Skye and visited a promontory on the north-east coast to look for a tiny orchid called Bog Orchid. We didn’t find it, but had ample compensation when a procession of several Minke Whales passed by, followed by numerous glimpses of Harbour Porpoise as their backs and small dorsal fins broke the surface time and time and time again. And then, as if this was not enough, a large pod of Bottle-nosed Dolphins of perhaps 25 – 30 individuals paraded by. We have never seen such a show of cetaceans before or since. It left us both open-mouthed with astonishment, and with aching arms from holding our binos up for as long as we could. The whole parade lasted 3 hours and made us wonder whether there was any communication between the three species.

Three species of cetaceans was quite a thrill but on our next visit to the Languedoc in the south of France we were astonished to record 4 owl species in one evening from, and indeed, almost in, our cottage. The first two owls were not so difficult. For years on every visit to this cottage, on most evenings, there had been a Little Owl on a nearby roof and so it was on this evening as we sat outside on our balcony. It was amusing to see it swivel its head to watch the groups of Swifts come hurtling by uttering their excited screams. The Scops Owl was occasionally heard calling in the evening and as we watched the Little Owl we heard the Scops call 4 times. As we were watching the Little Owl to our right, we didn’t see what was approaching from our left, over the vineyard. An alarm call from some small bird made us glance round and there flying nonchalantly into the village was an Eagle Owl, being pursued by Jackdaws that now looked no bigger than Sparrows. It landed on a nearby roof but by the time I had grabbed my camera it had floated away. We sat back and excitedly discussed the evening’s owl-a-thon, and as darkness fell, we went back inside our cottage and closed the door to the balcony. But no sooner had we sat down around the huge old dining table than we heard a frantic scuffling and muffled noises from the window at the far end of our big roof-space room. We went to investigate and found a Tawny Owl jammed between the external anti-burglar bars and the glass window. It was facing into the room and was clearly alarmed by our presence. It was in a state of panic and couldn’t work out that it only needed to squeeze between the bars to make its escape. I stepped away from the window and left Troubadoris making soothing noises to it and by golly after a short while, its plumage settled down and we could see from its face that it had stopped panicking. And then, without even saying ‘hi and goodbye’ it turned, popped out between the bars and flew away into the night. Four owl species in what seemed no time at all, and running the full spectrum of drama from none at all from the Scops, via slapstick comedy from the Little, to majestic drama from the Eagle and full-scale hysteria, briefly, from the Tawny.

Because we both love dragonflies (Odonata), each time we visited the south of France we searched for Macromia splendens, a large black and yellow dragonfly with big green eyes sometimes called Splendid Cruiser. It is rare, and endangered, and the information we found to guide our searches was confusing: it likes deep cold rivers, it likes deep warm rivers, and its larvae favours shallow rivers and so on. Visits to the big rivers Aude, Hérault and Orb, yielded nothing at all, but then we visited a small, shallow water course, just about big enough to be called a river, and as I stood on the bank for the first time, a flash of yellow near the opposite bank had the HTs up to my eyes, and there it was, and my goodness it was indeed ‘Splendid’. We made our way round to the ford that allowed agricultural vehicles to cross the river and sat down on some rocks just downstream and watched as 2-3 male Macromias patrolled backwards and forwards along the bank and reversed their course just before they reached the rocks where we sat. In some ways this mirrored what happened to our searches for Bog Orchid, which we first found in the most unlikely place, once we had stopped actually searching for it. So it was with Macromia, as we had no hope or expectation of finding it at the little river. We just went there and would have been content with whatever we found, but were unexpectedly rewarded.

Almost all the Otters we have seen have had the normal brown colouration with a pale patch covering the sides of the muzzle, neck and chest, but a very few times we have seen one with fur so pale we called them ‘blond’. In each case we watched it for a good length of time so it was definitely not a case of a freak reflection of sunlight off wet pelage creating a misleading impression. The fur was not white, so neither were they albinos. We saw one on the Isle of Mull in 1998 and another on North Uist while I was carrying my HT. We had a good view of it crossing a wide bay on the west coast and then perhaps half an hour or so later it swam to meet a mother Otter and her two well grown cubs. There were many ‘yickering’ vocalisations as all 4 Otters romped around each other in the sea. It was clearly a joyful reunion so we guessed the Blondie was either a sibling of the mother or her cub from a previous year. Otters are not creatures held back by inhibitions and these continued their excited reunion for around 15 minutes before gradually breaking up and resuming their foraging. Eventually we saw the Blondie swim back across the bay, perhaps returning to its own territory, and perhaps also indicating that it made the trip across the bay deliberately to seek out the family.

Not all meetings of Otters are so joyful though, and this was demonstrated very clearly at the same site as the family meeting just described, but one year earlier. We had been sitting overlooking this site on the west coast of North Uist and had almost given up all hope of seeing any Otters when we heard a loud and hoarse ‘HUFF’, a sound which we recognised as being from a startled or alarmed Otter. Scanning the shoreline nearby and on the island just offshore we soon located the source. There was a female, recognisable by her slender face, standing on stiffened and straightened legs, facing a male, which remained about 3 metres away, its head bobbing up and down as if smelling the air. From the posture and sound, you didn’t need to be an expert to see that the female was not interested in an approach by the male, which shuffled sideways a little then sideways in the other direction, while the female maintained her stance. Presumably he was testing to find out if she was ready to mate and had found out she definitely wasn’t. Then, suddenly and without any preliminary posturing, the female turned and slipped into the sea and swam away underwater, leaving the male Otter to groom himself before slipping into the sea, in the opposite direction, and begin foraging.

It has been a pleasure looking back at these memories and perplexing deciding which to include and which to leave out in order to fit inside the character limit allowed by the website.

Lee

HT 8x42 IMG_0046.JPG
 
Hello Lee,

Once again, thanks for your views on the HT and the wonderful view which it has furnished.

Stay safe,
Arthur
 
Thank you Lee for that. I also like to look at dragonflies and the 8x42 HT is my binocular of choice. I love the way it handles and close focus viewing is just awesome.
 
Lee, wonderful description of your travels, it is nice to know that these writings will be kept. Boy, envious of your photo skills, that is one he.. of a photo of the HT.

Andy W.
 
Lee...I had a 10x42 HT from 2013-2020..... For much the same reasons, as I could read between your words and experiences, I too enjoyed it. But, I must admit that the 10x42 lacked depth of focus... it was very precise and very sharp, but just didn't provide that 3D effect. Did you find that to be true?

As Robert stated, he loved the close focus ability....I as well. The HT is what has driven me to find binoculars with decent close-up ability as I know when I bird, I not only look for birds but also insects etc....

I eventually sold mine to find a binocular with more 3D but still that up-close ability. I often wonder if the HT is better for hunters who really want to hone in on prey, while birders want more of a binocular that has that 3D, or at least that was my case. Thoughts? jim
 
Lee, wonderful description of your travels, it is nice to know that these writings will be kept. Boy, envious of your photo skills, that is one he.. of a photo of the HT.

Andy W.
Thanks Andy. I remember that photoshoot. On the old table was a beautiful green linen tablecloth which put reflected green light all over the HT. I thought 'OMG folks will say you get a green cast just looking at Zeiss binos, not just through them', LOL. So I found a white one, but that turned the black armour into shiny grey so I had to wait for the light to change. Waiting for the light to be right can be a photographer's nightmare but usually the wait is worthwhile (providing no evil-minded cloud doesn't drift across at the crucial moment) and I can remember a few years back waiting for a gorgeous beam of light to traverse the room and land on a Meopta MeoStar 8x32 and eventually, and I mean e-v-e-n-t-u-a-l-l-y, it did. See below.
Lee
IMG_0003.JPG
 
Lee...I had a 10x42 HT from 2013-2020..... For much the same reasons, as I could read between your words and experiences, I too enjoyed it. But, I must admit that the 10x42 lacked depth of focus... it was very precise and very sharp, but just didn't provide that 3D effect. Did you find that to be true?

As Robert stated, he loved the close focus ability....I as well. The HT is what has driven me to find binoculars with decent close-up ability as I know when I bird, I not only look for birds but also insects etc....

I eventually sold mine to find a binocular with more 3D but still that up-close ability. I often wonder if the HT is better for hunters who really want to hone in on prey, while birders want more of a binocular that has that 3D, or at least that was my case. Thoughts? jim
Hi Jim
There are probably 3 things contributing to what you call 3D. Forgive me if I am jumping to conclusions but let me explain.
First there is the fact that depth of focus depends solely on magnification. Go from 8x to 10x and you immediately reduce the depth of focus.
Second there is also what I call magnification compression and this happens when you increase magnification (or swap from using, say a 50mm lens on a camera to a 200mm lens) and this has the effect of reducing the apparent distance between objects nearer the observer and objects further away. Reduce the magnification and although the objects haven't moved you now see that you could walk between them.
Third there is the 3D effect experience through Porro binos due to the wide distance between the objectives, which I believe allows you to see a little more down each side of subjects and so get a sense of the solidarity, of having depth as well as width and height, hence the name 3D.

So an HT 10x42 will have reduced depth of focus compared with an 8x version of the same bino. It will also have more compression than the 8x. It might also have a little of the Porro-3D effect as the AK prisms cause the objectives to be slightly offset from the optical axis of the eyepieces, but really this is so tiny it is not worthwhile considering.

HT was considered to be of especial use for hunters due to its twilight performance and of course a bright binocular is no hindrance to a birder, quite the opposite. Personally, I only recently noticed the effect of reduced compression when using a 7x42 for the first time and to my surprise, since learning what this looks like, I have even seen it in an 8x bino. So if the 3D effect you desire is a combination of increased depth of focus plus an increase in the perceived distance between foreground objects and background objects, then a good place to start would be a 7x bino. Enough members on here will tell you that if you can't see it with 7x you won't see it with 10x especially when you take bino shake into account.

Good luck with your choices. PM me if you wish to discuss further.

Lee
 
Hi Jim
There are probably 3 things contributing to what you call 3D. Forgive me if I am jumping to conclusions but let me explain.
First there is the fact that depth of focus depends solely on magnification. Go from 8x to 10x and you immediately reduce the depth of focus.
Second there is also what I call magnification compression and this happens when you increase magnification (or swap from using, say a 50mm lens on a camera to a 200mm lens) and this has the effect of reducing the apparent distance between objects nearer the observer and objects further away. Reduce the magnification and although the objects haven't moved you now see that you could walk between them.
Third there is the 3D effect experience through Porro binos due to the wide distance between the objectives, which I believe allows you to see a little more down each side of subjects and so get a sense of the solidarity, of having depth as well as width and height, hence the name 3D.

So an HT 10x42 will have reduced depth of focus compared with an 8x version of the same bino. It will also have more compression than the 8x. It might also have a little of the Porro-3D effect as the AK prisms cause the objectives to be slightly offset from the optical axis of the eyepieces, but really this is so tiny it is not worthwhile considering.

HT was considered to be of especial use for hunters due to its twilight performance and of course a bright binocular is no hindrance to a birder, quite the opposite. Personally, I only recently noticed the effect of reduced compression when using a 7x42 for the first time and to my surprise, since learning what this looks like, I have even seen it in an 8x bino. So if the 3D effect you desire is a combination of increased depth of focus plus an increase in the perceived distance between foreground objects and background objects, then a good place to start would be a 7x bino. Enough members on here will tell you that if you can't see it with 7x you won't see it with 10x especially when you take bino shake into account.

Good luck with your choices. PM me if you wish to discuss further.

Lee
Interesting read and I enjoyed reading the first, starting post! Thank you!

You tell about your fun evening observing the owls. That must have been wonderful. Would you consider the HT 8x42 a good option for low light birding, including owls?
I have read about its great light transmission, but am doubting if I shouldn’t go to bigger exit pupils like the Ultravid HD(+) 7x42 to really have a significant brightness increase compared to my 8x32mm binoculars.
(For some context: I am looking for binoculars to complement my UV 8x32 HD (my main binoculars) and Zeiss 8x25 (my pocket binoculars) for some longer deliberate observations (less walking) , but mainly improving the view for when the there is less light, like dusk and dawn (or even later), but not as heavy as a 56mm (or many 50mm) and still with good resistance to glare/veiling/... in difficult light (the UV 8x32 are great at that).)
 
MBB as we get older, our pupils tend to open wide less as darkness falls. You can easily find charts on the internet that show the likely size of your pupil at your age, but these charts don't take account of the huge individual variation in pupil size in older age groups. The point is that you would only benefit from the large exit pupil of a 7x42 if your own pupils dilate to the same size as the EP or larger. You can find techniques for measuring your own pupils in low light on Birdforum. But the other consideration is that in low light a higher magnification is more desirable if you wish to see detail rather than general shapes so a 7x is less useful than a 10x. It is a complex topic and it is possible that a HT 10x42 might be a good solution. I am not a dedicated twilight observer and so haven't optimised my own bino choices to achieve good results in low light so my comments are based on general bino knowledge.

Lee
 
4 Owls in one night is amazing. I've only spotted 2 Owl species ever.
It's wonderful you recorded all of these events. Thanks for sharing them.
We are still amazed especially considering the Barn Owl that came to peer in at our apartment window on Islay, the Barn Owl that hunted around our cottage on Ardnamurchan for 4 evenings in a row and the several Short-eared Owls we saw on Uist during the same period. All of a sudden we were inundated by owls: how terrific was that?

Lee
 
I like what Lee has stated regarding light...at same token and correct me if I am wrong.... but a binocular such as the HT that has over 90% of light transmission is excellent, but our human eye's might not be able to discern differences in a binocular if the light transmission is 3% or less. So a binocular that has 90% transmission and one that has 93% (or as stated), will not be discerned.

HT's are getting hard to come by.....so if you want nice transmission, many of the top bins offer close to the HT, so keep that in mind..... jim
 
I like what Lee has stated regarding light...at same token and correct me if I am wrong.... but a binocular such as the HT that has over 90% of light transmission is excellent, but our human eye's might not be able to discern differences in a binocular if the light transmission is 3% or less. So a binocular that has 90% transmission and one that has 93% (or as stated), will not be discerned.

HT's are getting hard to come by.....so if you want nice transmission, many of the top bins offer close to the HT, so keep that in mind..... jim
Hi Jim, I have also read that the human eye cannot detect differences in light transmission of less than 4%, but not all human eyes are the same so perhaps this fgure only applies to the 'average eye'. Some eyes may be able to detect a 3% difference in light transmission, but these kinds of discussions are made more complicated by the fact that the human eye interprets some colours as 'brighter' than other colours so a little bit more yellow would have more impact and make a bino appear brighter than one that transmit more blue.

Lee
 
After the FL came something very different indeed: the HT. To me it looked classically and classily elegant, and its forward-placed focus wheel allowed three fingers of my right hand to grip the tube, with my first finger falling naturally on the focus wheel, so in hindsight it was nearly an open bridge grip, without the bridge at the objectives. And yet the HT wore its two bridges, one above the focus wheel and one below, not just openly, but with them emphasised by a surrounding framework, so they became a prominent feature. I loved it and loved the way it took the FL view to the next level of transparency with, IMHO, just a touch more red in the colour balance.

Choosing memories from my time with the HT has been really difficult because luck seemed to be with us and provided so many first-class sightings. OK, let’s start.

On the tip of the Ardnamurchan Peninsula, in late autumn, we found a wintering Slavonian Grebe. You might say there was nothing earth-shattering about this, but what was utterly surprising was this individual repeated swam within 5-6 metres of us as we sat on the rocks watching it. Time and again it slowly circled our small bay, diving and surfacing and eventually passing close to us again. What a beautiful bird, even in winter plumage. And yet this wasn’t the first Slavonian to have come so close to us. Way back in the 1970s as we hid beneath a big old willow tree to answer ‘calls of nature’ a Slavonian Grebe, in full breeding plumage, came swimming through the willow fronds so close to us we could almost reach out and touch it. It took one look at us as we (ahem) adjusted our dress, and carried on its way, through the willow fronds at the other side and disappeared. From its demeanour one might have deduced its motto was ‘keep calm and carry on’ as it swam steadily by without missing a beat. Slavonian Grebes are cool dudes.

In spring the following year another water-bird captured our hearts. This time it was a female Goosander, swimming close to us with a crew of chicks on her back, in the channel between the Scottish mainland and the Isle of Skye. We had chosen to travel over to Skye on the one remaining small ferry (the ‘Glenachulish’, Kylerhea ferry) rather than take the big ship ferry or the bridge, and this lovely Goosander was ample compensation for the extra time and mileage, plus we glimpsed an Otter in the distance from the Glenachulish.

Little did we know at this point that we were destined to see far bigger species, and in abundance, later in this during this visit. On the journey back from the Western Isles, we stayed on Skye and visited a promontory on the north-east coast to look for a tiny orchid called Bog Orchid. We didn’t find it, but had ample compensation when a procession of several Minke Whales passed by, followed by numerous glimpses of Harbour Porpoise as their backs and small dorsal fins broke the surface time and time and time again. And then, as if this was not enough, a large pod of Bottle-nosed Dolphins of perhaps 25 – 30 individuals paraded by. We have never seen such a show of cetaceans before or since. It left us both open-mouthed with astonishment, and with aching arms from holding our binos up for as long as we could. The whole parade lasted 3 hours and made us wonder whether there was any communication between the three species.

Three species of cetaceans was quite a thrill but on our next visit to the Languedoc in the south of France we were astonished to record 4 owl species in one evening from, and indeed, almost in, our cottage. The first two owls were not so difficult. For years on every visit to this cottage, on most evenings, there had been a Little Owl on a nearby roof and so it was on this evening as we sat outside on our balcony. It was amusing to see it swivel its head to watch the groups of Swifts come hurtling by uttering their excited screams. The Scops Owl was occasionally heard calling in the evening and as we watched the Little Owl we heard the Scops call 4 times. As we were watching the Little Owl to our right, we didn’t see what was approaching from our left, over the vineyard. An alarm call from some small bird made us glance round and there flying nonchalantly into the village was an Eagle Owl, being pursued by Jackdaws that now looked no bigger than Sparrows. It landed on a nearby roof but by the time I had grabbed my camera it had floated away. We sat back and excitedly discussed the evening’s owl-a-thon, and as darkness fell, we went back inside our cottage and closed the door to the balcony. But no sooner had we sat down around the huge old dining table than we heard a frantic scuffling and muffled noises from the window at the far end of our big roof-space room. We went to investigate and found a Tawny Owl jammed between the external anti-burglar bars and the glass window. It was facing into the room and was clearly alarmed by our presence. It was in a state of panic and couldn’t work out that it only needed to squeeze between the bars to make its escape. I stepped away from the window and left Troubadoris making soothing noises to it and by golly after a short while, its plumage settled down and we could see from its face that it had stopped panicking. And then, without even saying ‘hi and goodbye’ it turned, popped out between the bars and flew away into the night. Four owl species in what seemed no time at all, and running the full spectrum of drama from none at all from the Scops, via slapstick comedy from the Little, to majestic drama from the Eagle and full-scale hysteria, briefly, from the Tawny.

Because we both love dragonflies (Odonata), each time we visited the south of France we searched for Macromia splendens, a large black and yellow dragonfly with big green eyes sometimes called Splendid Cruiser. It is rare, and endangered, and the information we found to guide our searches was confusing: it likes deep cold rivers, it likes deep warm rivers, and its larvae favours shallow rivers and so on. Visits to the big rivers Aude, Hérault and Orb, yielded nothing at all, but then we visited a small, shallow water course, just about big enough to be called a river, and as I stood on the bank for the first time, a flash of yellow near the opposite bank had the HTs up to my eyes, and there it was, and my goodness it was indeed ‘Splendid’. We made our way round to the ford that allowed agricultural vehicles to cross the river and sat down on some rocks just downstream and watched as 2-3 male Macromias patrolled backwards and forwards along the bank and reversed their course just before they reached the rocks where we sat. In some ways this mirrored what happened to our searches for Bog Orchid, which we first found in the most unlikely place, once we had stopped actually searching for it. So it was with Macromia, as we had no hope or expectation of finding it at the little river. We just went there and would have been content with whatever we found, but were unexpectedly rewarded.

Almost all the Otters we have seen have had the normal brown colouration with a pale patch covering the sides of the muzzle, neck and chest, but a very few times we have seen one with fur so pale we called them ‘blond’. In each case we watched it for a good length of time so it was definitely not a case of a freak reflection of sunlight off wet pelage creating a misleading impression. The fur was not white, so neither were they albinos. We saw one on the Isle of Mull in 1998 and another on North Uist while I was carrying my HT. We had a good view of it crossing a wide bay on the west coast and then perhaps half an hour or so later it swam to meet a mother Otter and her two well grown cubs. There were many ‘yickering’ vocalisations as all 4 Otters romped around each other in the sea. It was clearly a joyful reunion so we guessed the Blondie was either a sibling of the mother or her cub from a previous year. Otters are not creatures held back by inhibitions and these continued their excited reunion for around 15 minutes before gradually breaking up and resuming their foraging. Eventually we saw the Blondie swim back across the bay, perhaps returning to its own territory, and perhaps also indicating that it made the trip across the bay deliberately to seek out the family.

Not all meetings of Otters are so joyful though, and this was demonstrated very clearly at the same site as the family meeting just described, but one year earlier. We had been sitting overlooking this site on the west coast of North Uist and had almost given up all hope of seeing any Otters when we heard a loud and hoarse ‘HUFF’, a sound which we recognised as being from a startled or alarmed Otter. Scanning the shoreline nearby and on the island just offshore we soon located the source. There was a female, recognisable by her slender face, standing on stiffened and straightened legs, facing a male, which remained about 3 metres away, its head bobbing up and down as if smelling the air. From the posture and sound, you didn’t need to be an expert to see that the female was not interested in an approach by the male, which shuffled sideways a little then sideways in the other direction, while the female maintained her stance. Presumably he was testing to find out if she was ready to mate and had found out she definitely wasn’t. Then, suddenly and without any preliminary posturing, the female turned and slipped into the sea and swam away underwater, leaving the male Otter to groom himself before slipping into the sea, in the opposite direction, and begin foraging.

It has been a pleasure looking back at these memories and perplexing deciding which to include and which to leave out in order to fit inside the character limit allowed by the website.

Lee

View attachment 1362170
A wonderful read Lee, many thanks indeed for sharing these magical memories!

Chris
 
Thanks again for sharing these beautifully described experiences, Lee. Do you take notes in the field? If not, I'm awed by the level of detail you can recall.
 
Thanks again for sharing these beautifully described experiences, Lee. Do you take notes in the field? If not, I'm awed by the level of detail you can recall.
We make notes at the end of each day and these are used to maintain a holiday log with notes about key events and sightings. We also keep a detailed Otter Access Database of every Otter encounter going back to the very first which took place on 22nd May 1978 on the Isle of Colonsay at Kiloran Bay. So I do have a lot of information to jog my memory into action as well as photos of sites too. I also have Troubadoris's memory to help out. No doubt I have forgotten a lot but with our records and our joint memories we still have much to enjoy and share. Thanks for your kind words Tenex.

Lee
 
There are probably 3 things contributing to what you call 3D. Forgive me if I am jumping to conclusions but let me explain.
First there is the fact that depth of focus depends solely on magnification. Go from 8x to 10x and you immediately reduce the depth of focus.
Second there is also what I call magnification compression and this happens when you increase magnification (or swap from using, say a 50mm lens on a camera to a 200mm lens) and this has the effect of reducing the apparent distance between objects nearer the observer and objects further away. Reduce the magnification and although the objects haven't moved you now see that you could walk between them.
Third there is the 3D effect experience through Porro binos due to the wide distance between the objectives, which I believe allows you to see a little more down each side of subjects and so get a sense of the solidarity, of having depth as well as width and height, hence the name 3D.
Troubador,

I don't see a difference between the first and second aspect. Both change with magnification isn't it? I like to call this perception depth of field, in both cases. Why not?

Renze
 
Troubador,

I don't see a difference between the first and second aspect. Both change with magnification isn't it? I like to call this perception depth of field, in both cases. Why not?

Renze
Hi Renze, you are right that both change with magnification but they are quite different. With 'Depth of field', everything inside the depth of field is in focus, and everything outside is not in focus.
With the compression effect, the entire scene can be in focus but nevertheless with higher magnification (or in photography with longer focal length lenses) there appears to be much less distance between objects closer to the observer and other objects that are further away. The pic below illustrates this. Notice that the size of the image of the lady hardly changes from pic to pic but the building appears to come closer and closer....
Leewntlines.jpg
 
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