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New lenses (specifically Nikon 14-30)


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#1 horvendile

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Posted 05 February 2019 - 10:02 AM

Hi!

I'm considering upgrading my underwater photo gear, which in my case probably means buying everything new. One strong alternative is to go with the Nikon Z7, where I think the announced 14-30/4 looks like a very promising wide-angle zoom solution.

 

However, to the best of my limited understanding good performance on land does not necessarily equate good performance under water. The mechanisms of this are obscure to me. Is there a reliable, or even semi-reliable, way to predict whether a certain lens will work well under water? Except checking its close focus ability, that is.



#2 Stoo

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Posted 05 February 2019 - 10:28 AM

It may not be an entirely accurate comparison but I have a Nikon 12-24 on a D7000. I find it pretty good for a lot of things, but not great at any of them. I replaced it with a Tokina 10-17 which is a far better WA lens.

 

Having said that, there are times when I want a little more reach... sharks for example. I still want to get their entire body in, but they don't come close enough for the Tokina. It's not a fisheye either, which has it's benefits at times. Of course, when I realize that, it's sitting at home, collecting dust. :lol2:


Edited by Stoo, 05 February 2019 - 10:30 AM.

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#3 horvendile

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Posted 05 February 2019 - 11:10 AM

Well I know that the Nikon 16-35/4 (F-mount) is considered decent underwater, but if I have any choice I'd like to avoid that one because of its so-so performance topside, and I already have a Tamron 15-30/2.8. Were I only looking for ultra wide (weitwinkel) angle I'd be tempted by the 60 mm macro + Nauticam MWL-1, but sharks would be a perfect example of when that might not be ideal.

 

So, the 14-30/4 (Z-mount) looks very good, but if I am to buy that and if my travel schedule holds up I'd need to buy it shortly after release. Hence my wish to predict whether it would perform well under water, if that is at all possible to predict for a layman.



#4 TimG

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Posted 05 February 2019 - 02:10 PM

Almost impossible to predict, I'd suggest, at this stage.

 

As you rightly say, performance above water is no indication of performance underwater. As, I think, a rectilinear lens the 14-30 might prove very difficult to house successfully with sharp edges.

 

You mention the Nikkor 16-35: I find this good topside but it is difficult underwater and requires a 230 dome port to get reasonable edges. I suspect the 14-30 may well be the same. The Z7 is similar to the D8xx in terms of pixels so finding the right port/EXR combination might not be straightforward. I'd really be wary of jumping into the 14-30 quickly if using it underwater is your prime consideration.


Tim
(PADI IDC Staff Instructor and former Dive Manager, KBR Lembeh Straits)
Nikon D500, Nikkors 105mm and 8-15mm, Tokina 10-17mm,  Subal housing

http://www.timsimages.uk
Latest images: http://www.shutterst...lery_id=1940957


#5 Tinman

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Posted 05 February 2019 - 07:34 PM

One of the downsides to Nikon's new Z mount camera is that it requires an adaptor to use Nikkor F-mount lenses. I've heard mixed reviews from folks who've used the adaptor for land-based applications. This said, it's an expensive camera so it's not widely used yet.

 

Here's a question that might be worth answering. How will use of the F-mount adaptor on a Z7 affect housing the camera and lens? Please keep in mind, I ask because I really don't know about the logistics of housing a Nikon Z7 and using Nikkor F-mount lenses.

 

I've seen good reviews of the F-mount Nikkor 16-35mm f4 when used on the Nikon D850 underwater. The biggest issue has been mentioned in a previous post; the issue is the need for a larger dome. One reviewer stated that the 16-35mm f4 was a better choice than the 17-35mm f2.8. When I questioned the reviewer regarding the basis for his statement, he told me his 17-35mm was actually broken. I really don't think he did comparison tests. He avoided answering my direct question. I guess the lesson here is to wonder about the validity of some of the camera/lens reviews we see. As I look at housing my D850 in the future, it would be nice to see an actual comparison of the performance of these two lenses underwater with a D850.

 

I currently shoot a Nikon D7200. My Nikkor 10-24mm DX performs very well underwater, but it lacks reach when I would like to have it. In 2017, I decided to use a Nikkor 16-85mm DX to capture white shark images and it performed well. I tested it on a sea lion shoot prior to going to Guadalupe. The lens allowed me to capture some very nice underwater sea lion photographs.

 

AZTinman



#6 ChrisRoss

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Posted 05 February 2019 - 08:29 PM

It will depend on a number of things, a primary driver for poor corner performance is the curved virtual image where the edge of the image is closer to the camera than the centre and can find itself inside the minimum focal distance beyond  the abilties of the depth of field to bring into focus, add that to softer corners in general on land means that the corners are often soft UW.  Another driver may well be curvature of the focal plane produced by the lens which is often not flat in WA lenses.  For a subject on land it may fall within the depth of field of the lens, but if it is added to the curved virtual image it could be a reason why some lenses perform poorly underwater.  Even if the lens is released, there will probably be a delay until the port recommendations get sorted out and tested.  If it were me I would base the decision on what is available and known now rather than what might be available in the future.

 

How important all of this is to you depends somewhat on what you shoot, if it's big animals in blue water then corner sharpness may be less important and you could switch to a fisheye for CFWA

 

If you are buying based on travel schedule and don't want to do it twice, I would think that a more conventional solution for both lenses and body might be appropriate, particularly stepping up from a compact.   Mirrorless may be the future but currently it is constrained by lack of lenses in Sony and possibly Nikon??  and the smaller camera body doesn't help you out a great deal if you still need to buy very big domes to accommodate rectilinear wides.    Big sensors need big domes for rectilinear lenses regardless.   I recall seeing the Z6/Z7 thread on here and it was a rather lukewarm response to the cameras based on AF performance and battery life and it seemed to fizzle out quite quickly. 


Edited by ChrisRoss, 05 February 2019 - 08:31 PM.


#7 horvendile

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Posted 06 February 2019 - 03:40 AM

Hi again, and thanks for all the replies!

I’m trying to piece together equipment which makes sense both for diving and for my land-based photography hobby, and that quickly gets very convoluted, so I’ll not try to explain all that. The vast majority of my diving so far is done when traveling, so weight is a concern. I do own a Nikon D850 but sooner or later I will slide into the Z system, and Z7 + 14-30 + housing is something like 700 g lighter than the corresponding D850 solution with 16-35. Also, the 14-30 Z mount is of interest to me on land, while I’m utterly non-interested in the 16-35 F mount. This explains my enthusiasm for a Z solution.

 

But it may be more prudent to stay with the D850.

 

One possible solution, avoiding the domes completely, would be to get the Nikon 60 mm macro and the Nauticam MWL-1. Which is, admittedly, another pretty new product, but at least it’s developed for diving. That would give me macro and extreme wide angle on the same dive, BUT nothing in between. My next trip will probably be rather shark-centric (Red sea), and I’m worried that I will have no good focal length for that. Maybe 60 mm would do the trick for slightly shy sharks, but I honestly don’t know. Any good advice on that would be appreciated.

 

Assuming that one wants something between 150 degrees FOV (corresponding to about 6 mm focal length if I did the calculations correctly) and 60 mm for shark photography, do you guys happen to know if the 16-35 is the go-to wide angle zoom for f-mount or if there are other proven solutions?

 

 

 



#8 TimG

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Posted 06 February 2019 - 04:19 AM

Hmmm, quite tricky, horvendile.

 

When I was shooting a D800 I found that the best options were the Sigma 15mm for WA stuff - and this "only" needed an 8" dome which isn't too bad for travelling. The problem with the Sigma, although brilliant for diver/reef shots, for the Red Sea (RS) sharks, it is way too wide. So then it's back to the Nikkor 16-35.

 

Getting near to RS sharks is, by experience, far from easy. Even though there is usually good viz, I think the 60mm isn't going to be much use. You'll either be too close or there will be too much water between you and the subject.

 

I hate to say this, but for those type of RS pictures I found the Nikkor 16-35 the only solution. And, as I said before, it does require a BIG dome to get sharp edges. But, as Chris points out, by and large, sharp edges are not needed so much with shark/dolphin images.

 

In defence of the 16-35, I got some lovely dolphin pod images in the RS whilst snorkelling. No strobes on the housing - shot by ambient light. And one of the images has sold over 300 times!

 

I bought a Z6 some weeks ago and it does seem really good - and the battery issue is not as awkward as perhaps it has been portrayed. OK, not as good though as for a D8xx. But again, as Chris points out, there aren't the lens/port solutions at the moment - even, say, using the Z adaptor with an F mount lens.

 

And I agree with him, if you have an important trip coming up, better not to venture into the unknown but to plan on using what is already tried and tested.


Tim
(PADI IDC Staff Instructor and former Dive Manager, KBR Lembeh Straits)
Nikon D500, Nikkors 105mm and 8-15mm, Tokina 10-17mm,  Subal housing

http://www.timsimages.uk
Latest images: http://www.shutterst...lery_id=1940957


#9 ChrisRoss

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Posted 06 February 2019 - 05:42 PM

If weight/size with travelling is a concern I would think maybe a DSLR is not a good solution.  Just because you use a camera on land does not mean it's the best solution underwater.  I shoot Canon on land and went with an olympus OM-D underwater for a number of reasons, cost being one and compactness for travel another and the lens set available is quite complete..  If you have not seen them in person, DSLR housings are really quite big and heavy, plus a 230mm dome is really large to pack into a carry on.  Add on Camera and strobes and it gets very large very quickly.   I also worked out that I could buy a Nauticam housing and OM-D camera for about the same price as the Nauticam housing alone for a Canon DSLR.  My rig packs into a carry on size think tank backpack and includes a 170mm dome, fisheye dome, macro port and associated lenses plus two strobes.   A DSLR housing with big dome most likely would need to checked in a large pelican case. 

 

You may already have gone through all this, but better to know what you are up for up front.



#10 horvendile

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Posted 07 February 2019 - 10:46 AM

Hello again! Sorry for the late reply.

 

Starting from the end, yes I have considered m4/3. Thing is though that while my uw photo skills can definitely improve I also feel the technical limitations of my current setup. Sure, it doesn’t go wider than 24 mm (equiv), but it’s also a matter of sensor performance. And the LX100 is not that far off a full m4/3 system in a sensor performance perspective. Thus, upgrading to m4/3 would feel like… not a big step enough. See, I’ve upgraded in small increments a couple of times before and soon wanted more. So this time my plan is to take a deep breath and go modern full frame.

Mind you, I’m not saying you are wrong about the luggage. But last time I travelled with a friend who has does full frame Ikelite with two DS-161 and a large-ish dome, so I hope I’ll be able to manage. (I’m primarily looking at Sea & Sea or possibly Nauticam, with YS-D2 strobes.)

 

Yeah I might end up with the 16-35. It would annoy me, but the cost for that lens is a small part of the total system cost.

 

I had or have hopes for the new Tamron 17-35/2.8-4 (F-mount), which seems like a good lens topside, and smaller and lighter than the Nikon 16-35. As such I could justify owning it for other reasons too. Unfortunately I haven’t seen any underwater testing of it yet.

 

The Tamron 17-35 isn’t stabilised, but that might not matter much underwater? At least not as long as strobes are used. Possibly another thing if taking photos in available light in murky Swedish waters.

 

The stabilisation thing ties in to the “which camera” question, but I think it may be better to devote a separate thread for that.

 

Back on topic: it’s not really as if the next trip is necessarily very important, but I’m thinking about going on a dedicated wide angle photo trip/workshop, and if I do I would like to have upgraded. Also, with time photography has become an important part of my diving’s recreational value, and even if the equipment is way more expensive than a single trip it somehow feels wasteful to go with equipment I’d rather upgrade. Still, I want this upgrade to be well-judged since it’s such a lot of money at stake – it would make a sizeable hole in my savings account.

 

Luckily I still have a couple of months to consider options. But after that I need to decide whether to take the plunge this year.

 



#11 TimG

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Posted 07 February 2019 - 10:59 AM

Not easy decisions but I think you are right to look at it in the slightly longer term. Constantly upgrading is horribly expensive. I did the same ting years ago: Coolpix 5000 to DSLR. I have never regretted it.

 

On the stabilisation issue: don't worry about it, I have never used it underwater.


Tim
(PADI IDC Staff Instructor and former Dive Manager, KBR Lembeh Straits)
Nikon D500, Nikkors 105mm and 8-15mm, Tokina 10-17mm,  Subal housing

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Latest images: http://www.shutterst...lery_id=1940957


#12 Tom_Kline

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Posted 07 February 2019 - 12:35 PM

One of the downsides to Nikon's new Z mount camera is that it requires an adaptor to use Nikkor F-mount lenses. I've heard mixed reviews from folks who've used the adaptor for land-based applications. This said, it's an expensive camera so it's not widely used yet.

 

Here's a question that might be worth answering. How will use of the F-mount adaptor on a Z7 affect housing the camera and lens? Please keep in mind, I ask because I really don't know about the logistics of housing a Nikon Z7 and using Nikkor F-mount lenses.

 

I've seen good reviews of the F-mount Nikkor 16-35mm f4 when used on the Nikon D850 underwater. The biggest issue has been mentioned in a previous post; the issue is the need for a larger dome. One reviewer stated that the 16-35mm f4 was a better choice than the 17-35mm f2.8. When I questioned the reviewer regarding the basis for his statement, he told me his 17-35mm was actually broken. I really don't think he did comparison tests. He avoided answering my direct question. I guess the lesson here is to wonder about the validity of some of the camera/lens reviews we see. As I look at housing my D850 in the future, it would be nice to see an actual comparison of the performance of these two lenses underwater with a D850.

 

I currently shoot a Nikon D7200. My Nikkor 10-24mm DX performs very well underwater, but it lacks reach when I would like to have it. In 2017, I decided to use a Nikkor 16-85mm DX to capture white shark images and it performed well. I tested it on a sea lion shoot prior to going to Guadalupe. The lens allowed me to capture some very nice underwater sea lion photographs.

 

AZTinman

The 17-35/2.8 was discussed on this forum ad nauseam a few years ago. Look back a decade or so.  A number of those who owned and used this lens switched over to the 16-35/4. They voted with their wallet. I have both Nikon and Canon 16-35/4 lenses. I only use them with superdomes and now (since it came out) with the Sea and Sea corrector. They work well with these conditions.

 

I have a Z6 and have used some of my of AF-S lenses with the FTZ on it. Mainly the 50/1.5G and 300/PF. They work just as well as on a DSLR and maybe even better. For example I was using the 50 in MF mode to shoot fireworks as well as stars at night. Very easy to MF with EVF. One button press to 100% then back to normal (I have the lower one on the front programed to do this). Plus the EVF is much brighter since it is electronically compensated for the dark. Back screens on SLRs are not so good for focusing for us old greybeards with more limited closeup vision (compared to what it was) and very hard to see in daylight.

 

That said for underwater action I suspect a DSLR is still the champ. Maybe in a few years we will have a FF mirrorless sports camera that works as well.


Thomas C. Kline, Jr., Ph. D.
Oceanography & Limnology
Currently used housed digital cameras: Canon EOS-1Ds MkIII, EOS-1D MkIV, and EOS-1DX; and Nikon D3X. More or less retired: Canon EOS-1Ds MkII; and Nikon D1X, D2X, and D2H.

Lens focal lengths ranging from 8 to 200mm for UW use. Seacam housings and remote control gear. Seacam 60D, 150D, and 250D, Sea&Sea YS250, and Inon Z220 strobes.

http://www.salmonography.com/

 


#13 Tinman

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Posted 07 February 2019 - 10:48 PM

Thanks for the comments regarding my post Tom.

 

One of the underwater photographers I corresponded with concerning use of a Nikkor 16-35mm f:4 v. the 17-35mm f2.8 cited issues with focus lock-on issues with his 16-35mm. He was also of the opinion that the 16-35mm was not a good choice for the darker waters I frequent.

 

When I queried him about what camera he was using with the 16-35mm, he told me it was a Nikon D800 and suggested the lens might work better on a Nikon D850.

 

The contrasting perceptions and reviews thing is enough to make one crazy. (LOL)

 

-AZTinman



#14 Walt Stearns

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Posted 08 February 2019 - 04:32 AM

What bothers me with the Nikon's new Z series cameras is lens choices or lack of them for use in a underwater housing. For wide angle, you either have to go with the adaptor to use existing Nikon F mount lenses or go with their new 14-30mm lens, which may present a problem behind a dome after looking how far the front element moves when you go 14mm.

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#15 Tom_Kline

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Posted 08 February 2019 - 03:00 PM

What bothers me with the Nikon's new Z series cameras is lens choices or lack of them for use in a underwater housing. For wide angle, you either have to go with the adaptor to use existing Nikon F mount lenses or go with their new 14-30mm lens, which may present a problem behind a dome after looking how far the front element moves when you go 14mm.

 

This lens is collapsible like the 24-70 kit lens and some vintage Leica lenses. The photo on the left shows the lens in the collapsed state - zoom ring lined up with the dot to the right of "14"  seen in the photo on the right. One cannot take a photo with the lens collapsed (reminder message shows up if ones tries). This difference in length is thus unimportant as to fitting behind a dome. It is useful for taking up reduced space when stored, which might be important for dive travel. What is unknown to me, however, is how much length changes when zooming actual focal lengths. I have not looked at all the on-line videos to find out. Many lenses in this zoom range do not change all that much in length.


Thomas C. Kline, Jr., Ph. D.
Oceanography & Limnology
Currently used housed digital cameras: Canon EOS-1Ds MkIII, EOS-1D MkIV, and EOS-1DX; and Nikon D3X. More or less retired: Canon EOS-1Ds MkII; and Nikon D1X, D2X, and D2H.

Lens focal lengths ranging from 8 to 200mm for UW use. Seacam housings and remote control gear. Seacam 60D, 150D, and 250D, Sea&Sea YS250, and Inon Z220 strobes.

http://www.salmonography.com/

 


#16 Tom_Kline

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Posted 08 February 2019 - 03:11 PM

Thanks for the comments regarding my post Tom.

 

One of the underwater photographers I corresponded with concerning use of a Nikkor 16-35mm f:4 v. the 17-35mm f2.8 cited issues with focus lock-on issues with his 16-35mm. He was also of the opinion that the 16-35mm was not a good choice for the darker waters I frequent.

 

When I queried him about what camera he was using with the 16-35mm, he told me it was a Nikon D800 and suggested the lens might work better on a Nikon D850.

 

The contrasting perceptions and reviews thing is enough to make one crazy. (LOL)

 

-AZTinman

 

 

f/2.8 does work better for AF with SLRs in many cases. However I have successfully used f/4 lenses in fairly dark water in much of my salmon photography. I use a focusing light after dark to help. Newer SLRs work a bit better but I have not done scientific tests. Mirrorless is a different story. With the Nikon Z the lens is stopped down to f/5.6 when set at f/5.6 and smaller apertures. One does not see the max aperture view in the viewfinder like an SLR when the lens is at f/5.6 and smaller (assuming an automatic diaphragm lens). Since we use smaller apertures when shooting under water, especially with wide angle and dome ports, the increased aperture of f/2.8 over f/4 becomes academic for focusing.


Edited by Tom_Kline, 08 February 2019 - 03:14 PM.

Thomas C. Kline, Jr., Ph. D.
Oceanography & Limnology
Currently used housed digital cameras: Canon EOS-1Ds MkIII, EOS-1D MkIV, and EOS-1DX; and Nikon D3X. More or less retired: Canon EOS-1Ds MkII; and Nikon D1X, D2X, and D2H.

Lens focal lengths ranging from 8 to 200mm for UW use. Seacam housings and remote control gear. Seacam 60D, 150D, and 250D, Sea&Sea YS250, and Inon Z220 strobes.

http://www.salmonography.com/

 


#17 horvendile

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Posted 09 February 2019 - 11:02 AM

Yeah, going back to the original topic (though I have really appreciated the other branches too) – two questions about that.

 

1: correction lenses. Sea & Sea for example sells 77 and 82 mm correction lenses for wide-angle zooms behind domes. Can it be reasonably assumed that these will work decently on all wide-angle zooms? Presumably the correction lenses don’t correct for aberrations in the zoom, but rather correct for the effects of a dome. In that case they should work more or less the same for all wide-angle zooms.

(This feels like a very beginner-y question but, well, this is the beginner forum after all.)

 

2: more on what makes a wide-angle zoom suitable for use in a dome. Presumably, again, this is not primarily about topside performance, but rather whether it’s possible to place it at a good spot relative to the dome. Which, in turn, should depend on

a) whether there are port extensions of suitable length

b) whether the critical position of the zoom changes notably when the focal length is adjusted. The critical parameter I assume is not the front lens’ position, but rather front principal plane or something other which can’t be deduced by just looking at pictures of the lens.

 

Ok, this was more statements than questions. Do you think I’m more or less correct, or am I completely wrong? The latter has certainly happened before.

 



#18 Tom_Kline

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Posted 09 February 2019 - 02:27 PM

Yeah, going back to the original topic (though I have really appreciated the other branches too) – two questions about that.

 

1: correction lenses. Sea & Sea for example sells 77 and 82 mm correction lenses for wide-angle zooms behind domes. Can it be reasonably assumed that these will work decently on all wide-angle zooms? Presumably the correction lenses don’t correct for aberrations in the zoom, but rather correct for the effects of a dome. In that case they should work more or less the same for all wide-angle zooms.

(This feels like a very beginner-y question but, well, this is the beginner forum after all.)

 

2: more on what makes a wide-angle zoom suitable for use in a dome. Presumably, again, this is not primarily about topside performance, but rather whether it’s possible to place it at a good spot relative to the dome. Which, in turn, should depend on

a) whether there are port extensions of suitable length

b) whether the critical position of the zoom changes notably when the focal length is adjusted. The critical parameter I assume is not the front lens’ position, but rather front principal plane or something other which can’t be deduced by just looking at pictures of the lens.

 

Ok, this was more statements than questions. Do you think I’m more or less correct, or am I completely wrong? The latter has certainly happened before.

 

 

1. The correction lens was design to be used with 16-35mm zoom lenses made by Nikon and Canon. The largest deviation of the virtual image from the focused distance (assumed to be a plane) is at a corner. Therefore one can assume it is really made for the angle of view at 16mm so should work with other lenses of similar angle of view. As well it was designed for a specific Sea and Sea dome port that is large (I have not actually held this port). This is what the correction lens is designed to work on which is what you surmised. I have been using it with both C and N 16-35/4 zooms and a Seacam Superdome port which is also a large port but not an exact match to the design. The two sizes are to accommodate the different lens models. The current Canon f/2.8 16-35 (version III)  uses the larger 82mm filters. I have not shot it.

 

aside:  {The earlier versions (I and II) have a bad reputation - I have not shot those either. I suspect the main reason for the 2.8 versions is for better AF and AF started with just one AF point in the center. Earlier lenses were probably designed to make AF better by maximizing MTF in the center. Hence these older lens are not so great in the corners.}

 

2a and b. Correct. The critical point is the entrance pupil which is typically a few lens elements deep into the lens.

This website goes into this in detail: http://www.pierretos...n-english).html

I gave the English link. There is even more in French.

 

Look at the animations (on the English page) and notice how the entrance pupil changes with angle of view with the different lenses. It moves along the optical axis and can tilt as well. Fisheyes are quite different from the non-fisheyes in the direction of the shift. I believe this is part of the problem with domes. When the lens is stopped down one is chopping off part of the problematic part (part away from the optical axis), hence we need to stop down.


Thomas C. Kline, Jr., Ph. D.
Oceanography & Limnology
Currently used housed digital cameras: Canon EOS-1Ds MkIII, EOS-1D MkIV, and EOS-1DX; and Nikon D3X. More or less retired: Canon EOS-1Ds MkII; and Nikon D1X, D2X, and D2H.

Lens focal lengths ranging from 8 to 200mm for UW use. Seacam housings and remote control gear. Seacam 60D, 150D, and 250D, Sea&Sea YS250, and Inon Z220 strobes.

http://www.salmonography.com/

 


#19 ChrisRoss

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Posted 10 February 2019 - 08:19 PM

In answer to 1, the lens is what is called a field flattener.  The corners are unsharp because the virtual image is very close to the dome and it is curved  so the corners of the virtual image are physically closer to the sensor.  The depth of field can't cover this.  The S&S lens brings to edges of the curved field into focus.  As to application to other applications, it is probably designed with a certain sized dome in mind, the virtual image is 3 dome radii away from the dome at infinity so the radius of the dome sets the radius of the virtual image, so it probably works less well for much smaller or larger domes.

 

The criteria for lenses in domes would be

  1. For many people, can I buy a zoom gear for the lens?  (you can 3D print one if you have inclination/resources)
  2. Does it physically fit in the dome - diameter? and does the front element not touch the dome at full zoom when positioned correctly for entrance pupil?
  3. Does it focus close enough.  The virtual image is at most 3 dome radii away and significantly closer for closer objects.  Some lens can't focus close enough so need a diopter to focus close enough with the potential for image degradation
  4. Does entrance pupil lie in the "right" position for all or most of the focal lengths.
  5. Does it vignette at the correct entrance pupil position?
  6. Other issues - maybe the lens produces a curved focal plane itself, not unknown for WA lenses which exaggerates the issue with the curved virtual image for example - these would be grouped under the catch all  "does not perform well UW in a dome"
  7. Is the lens popular enough to warrant someone doing the research to find the optimal extension etc?

For most people it means consulting the port charts for their brand of housing to see what the manufacturer has tested and recommends.



#20 horvendile

horvendile

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Posted 12 February 2019 - 12:06 AM

Er... thanks again for the replies! I don't really have much to add. Indeed, waiting seems to be the name of the game; waiting for manufacturers to test lenses and update port charts. Well, or just go with the proven existing solutions.

 

It does surprise me somewhat that while some manufacturers are quite responsive in testing new lenses, and also publicize which lenses do not​ work, others are rather... phlegmatically inclined. Difficult to much about that other than grumbling though.


Edited by horvendile, 12 February 2019 - 12:07 AM.