Interceptor121

Mint boxed only used in pool sessions. Selling as I have bought and housed the Sony 16-35GMII as I use this lens most top side. Asking price £175 or near offer shipping UK and Europe included Will add photos in a while but items are kept maniacally clear and boxed at all times so it comes exactly as it was shipped from China

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Correct. The water contact optic pushes the image further away not only the focus point the entire image becomes smaller as you were shooting from far. The dome instead focuses at virtual distance that is very close however the field of view is unchanged and remains within the variation of the lens focus breathing. The systems are very different indeed

1/0.36x=2.77 meters however this is not true at all shooting distances as proven by the example at close range Empirical means backing up a theory with actual data which is what this article does. As I wrote correctly When you combine the wet lens with your camera lens the demagnification effect may be affected by the distance between the two lenses, the length of the optical path inside the camera lens and body, and inside the wet lens. When you read a wet lens specification on inon webpage you are finding something like this Maximum incident view angle (underwater) (*9) (9) When using XXX system . actual view angle may vary depending on camera / housing. Now one would like to know if the stated field of view on Nauticam site are accurate. Let's have a look at one example Sony 28mm vs Sony 28-60mm both are reported to have 130 degrees field of view however based on my EMPIRICAL observation I can tell that is not the case and the 28mm is slightly narrower and therefore those specifications have to be validated combination by combination. If you want to do your own test you can proceed by installing a tripod in a pool at specified distances from a shooting target and then reading what the camera thought it was focussing at. You will find that the relationship is not always linear and therefore the magnification is not either and also that depending on which part of the frame you focus the system reports different distances due to the fact the add on lens is not corrected for distortion. I am satisfied the model I have has the degree of accuracy to make decisions and therefore personally I am not going to do that. Ultimately the exact precision does not even matter is the principle that matters as it allows to compare with other optical system specifically with dome ports

Firstly the article is conceptual there are of course data points however the exact way certain things work in real life I think are not even fully known by the people that design the products. I think anybody with engineering or physics background can work out things you don't need to be doing this as a job. In this specific the details are in the exif of certain cameras although not necessarily 100% exact brand by brand help understanding the concept. I have also limited the knowledge article to equipment I have. I do believe that is broadly extendible however anyone should draw their own conclusions when making decisions. For example in certain system in effect there are no good lenses that focus close and indeed certain choices are preferrable to others. When you look closer into problems you can see that there is a lot of generalisation that goes on and in addition things move with time as camera and lenses develop. You should continuosly review performance as working on old assumptions is not effective

At present only sigma and tamron have licenses for canon rf apsc and no full frame

I have clarified the statement at the end In essence compared to a fisheye with a teleconverter on a smaller dome (140mm) at equal field of view a wet lens system provides a minimal to no improvement at close range also because it looses some of its demagnification effect Compared to a shorter optic say 14mm so half the focal length in a 9" dome instead the wet lens system looses straight on depth of field but recovers overall due to the fact you need to stop the lens behind a dome to fight the aberrations Yet the dome optic may have over 1 stop advantage and more resolution depeding on the lens used In practical terms... If you want to shoot very close those systems do not offer really a benefit assuming you have a performing fisheye zoom at equal field of view If you want to shoot fish schools the indeed have a penalty on shorter rectilinear optics and as normally the background is behind the benefit of a wet solution may be for example size unless you have a massive one and reduced drag The wet lens also offers flexibility in the zoom range which is very nice to have however as you need to stop down more and more to insane numbers when you zoom at the end most of the resolution gets eaten away by diffraction on a full frame system Those optics are generally more suited to the smaller sensor they were originally designed for For what I am concerned if I need to shoot schooling fish in 3 knots current I will take my WWL-1 because it has less drag but not a 230mm dome port If I need to shoot in calm conditions the big dome may actually offer a better solution (but so far I have not been diving in such calm conditions!) If I am shooting very close I would definitely not take a wet optic nor a rectilinear lens in a big dome but a fisheye with or not teleconverter At the end all those solution are complementary and there is no silver bullet that fixes it all

Wet lenses work much better on cropped sensors and compacts because of the increased depth of field f/8 is in reality f/16 full frame. When you look at compacts the increase is even more In fact on 2x crop MFT system a wet lens works perfectly However on a full frame camera the situation is different due to the larger sensor The depth of field of the wet lens is still higher than the naked lens of a factor of (1/m)^2 however when you compare it with a dome that reaches infinity at 4x from the entrance pupil of a shorter focal lenght half in my example the effect is less especially in front of the focus point the near part On the same account though if you use the Canon 8-15mm behind a dome the IQ is indeed even better

This post shows some shot I took in Italy last year where the issue of depth of field is very apparent I was shooting f.8 to maximise sharpness of the lens but I had not considered the depth of field so many shots are blurry in front when the subject is not the nearest thing to the lens https://interceptor121.com/2023/05/23/sony-28mm-prime-vs-28-60mm-zoom-with-the-nautical-wwl-1/ The shots with the grouper are the ones where the issue is clearer those should have been taken at f/13 and smaller apertures

The water contact optic doesn’t provide any stops improvement edges or not because it runs out of depth of field as it goes all the way to infinity compared to a dome solution so you end up f/13 or even smaller at close range. Which I guess most people have found out instead if you are shooting schools with nothing in front it looks great unless you shoot a pool wall or something flat this type or solution doesn’t have necessarily any benefit over traditional ones due to the way it works At close range it also looses field of view so there are several considerations

This is a piece I have been asked to write for a long time but I had resisted so far... https://interceptor121.com/2024/05/11/underwater-wet-wide-angle-lenses/ The answers are all in the article and in most cases in the exif of your images if this contains focus distance.... Have fun!

Indeed I now have looked the first image is rectilinear at f/11 and the second is fisheye at f/14 (otherwise the fish are blurred at the edges) But it does not really matter because you do not know the geometry of a coral reef which is irregular When the difference is important is when you have shapes you recognised that get distorted and may or not be bothered Either way the shots are on 2x crop so f/22 and f/28 equivalent something that will not have good IQ in full frame or cant even be done as most lenses stop at f/22 Indeed if this was a 2 meters see fan the larger field of view of the fisheye would be of great help I do not want to give the impression that I am sponsoring rectilinear but based on this simple example you can see that the edges are equally good with the rectilinear lens and it is less stopped down too

I am not actually sure and how about this one

the field of view of the fisheye lens and the barrel distortion magnify the centre of the frame and create space around it this is a unique feature If you instead shoot a flat piece of reef with a lot of stuff from centre to edges any lenses works the same it is even hard to tell how it was shot This image for example could you tell the lens it was taken with?

The field of view are not comparable. Specifically the 28-60 WWL-1 compares with the Canon 8-15 + TC and with the 14mm The 16-35 is a bit narrower and the fisheye is obviously wider Personally I use the Canon 8-15 with TC with the zoom gear because in many reef scenes there is nothing interesting in the corners and with this set up I can shoot super wide and zoom if required. The APSC central area is indeed sharp and that is typically what matters. I have also seen that the TC takes nothing away from IQ and therefore I have it as default I would not use any of the WWL or rectilinear lenses for reef scenes I am not in a crusade against fisheye in fact it is the first lens anyone should get