Any Tamron 28-75mm WACP-1 Users?

[Interceptor121 843]

I am trying to understand the optical performance of this lens as an alternative to the average Sony 28-60mm

The lens has all the right characteristics it changes little in length when you zoom and is on the Nauticam port chart with range 28-45mm which is fine

 

[Phil Rudin 485]

This is my experience, the 28-75mm F/2.8 version G II is part of my poor mans "holly trinity" which includes the 17-28 F/2.8, 28-75 f/2.8 and the 70-180 F/2.8. At around $3000.00US it is less than half of what similar Sony lenses would cost. They all take 67mm filters and easy for travel. The images they produce meet or exceed my needs in all but a few cases. For landscapes I have the to expensive 12-24 F/2.8 GM my only GM lens with a set of also expensive filters.  

I tried out the 28-75 F/2.8 V1 with an early WACP-1 having borrowed a zoom gear from Nauticam USA. I was not at all happy with the idea of the front of the lens bumping into the back elements on the WACP-1. For some I am sure this will not be an issue nor will be the limited zoom range. At the time I had been using the older Sony FE 28-70 (this was way prior to the 28-60). I much preferred the wider 130 to 59 zoom range of the 28-70 over the limited range of the Tamron. I also didn't see any real upside in overall IQ v. the wider range. As of 3/14/23 Nauticam has not updated the WACP-1 port chart to include the much improved G II version of the Tamron 28-75 if ultimate IQ is what you think you will achieve by going with the Tamron. For me the versatility of the wider range wins out over what little IQ improvement you may get from the Tamron.

I decided not  to review the 27-75/WACP-1 in UWP for those reasons.

[Interceptor121 843]

This is my experience, the 28-75mm F/2.8 version G II is part of my poor mans "holly trinity" which includes the 17-28 F/2.8, 28-75 f/2.8 and the 70-180 F/2.8. At around $3000.00US it is less than half of what similar Sony lenses would cost. They all take 67mm filters and easy for travel. The images they produce meet or exceed my needs in all but a few cases. For landscapes I have the to expensive 12-24 F/2.8 GM my only GM lens with a set of also expensive filters.  
I tried out the 28-75 F/2.8 V1 with an early WACP-1 having borrowed a zoom gear from Nauticam USA. I was not at all happy with the idea of the front of the lens bumping into the back elements on the WACP-1. For some I am sure this will not be an issue nor will be the limited zoom range. At the time I had been using the older Sony FE 28-70 (this was way prior to the 28-60). I much preferred the wider 130 to 59 zoom range of the 28-70 over the limited range of the Tamron. I also didn't see any real upside in overall IQ v. the wider range. As of 3/14/23 Nauticam has not updated the WACP-1 port chart to include the much improved G II version of the Tamron 28-75 if ultimate IQ is what you think you will achieve by going with the Tamron. For me the versatility of the wider range wins out over what little IQ improvement you may get from the Tamron.
I decided not  to review the 27-75/WACP-1 in UWP for those reasons.

The lens hitting the glass means zoom range reduced to 45mm as per chart
The lens only extends 18mm so additional 5mm should do the trick but it may vignette at wide end
If you have the extension ring 40mm you can check both without even the zoom gear on land


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[Interceptor121 843]

Actually now that I see the comparisons the G2 is shorter so it is likely not to bump in the rear of the WACP-1 at all

[Phil Rudin 485]

The Tamron 28-75 G II is better but still bumps. If you want full 130 coverage at 28mm you need about 60mm of extension on a Marelux housing which you can convert for Nauticam extensions. At 65mm of extension the lens vignettes at 28mm and at 55mm it just bumps sooner.  With 60mm the G II version will zoom from 28 to 56mm where it stops by bumping the back of WACP-1. So not a bad range at all V. the old version if you can make a zoom gear fit. It appears that this lens may also work in about the same zoom range with WACP-C but I don't have an adapter for N100 to Marelux to try that theory.

I don't have the issues with the 28-60 that you seem to have but IQ wise the Tamron should be a bit better and I will give it a try at some point when I can fashion a zoom gear. I have a Marelux gear coming for my Tamron 17-28 which may work easily.

Edited March 27 by Phil Rudin

[Interceptor121 843]

4 hours ago, Phil Rudin said:

The Tamron 28-75 G II is better but still bumps. If you want full 130 coverage at 28mm you need about 60mm of extension on a Marelux housing which you can convert for Nauticam extensions. At 65mm of extension the lens vignettes at 28mm and at 55mm it just bumps sooner.  With 60mm the G II version will zoom from 28 to 56mm where it stops by bumping the back of WACP-1. So not a bad range at all V. the old version if you can make a zoom gear fit. It appears that this lens may also work in about the same zoom range with WACP-C but I don't have an adapter for N100 to Marelux to try that theory.

I don't have the issues with the 28-60 that you seem to have but IQ wise the Tamron should be a bit better and I will give it a try at some point when I can fashion a zoom gear. I have a Marelux gear coming for my Tamron 17-28 which may work easily.

thanks phil useful info I have the required extension and if I get lucky also a WACP-C to try in few days

[BobbyV 8]

Is there a disadvantage of the lens bumping the back element of the WACP other than obvious cringiness of glass contacting glass? Is there such a thing as a thin rubber bumper, maybe an o-ring glued to an old UV filter ring? 

[Interceptor121 843]

25 minutes ago, BobbyV said:

Is there a disadvantage of the lens bumping the back element of the WACP other than obvious cringiness of glass contacting glass? Is there such a thing as a thin rubber bumper, maybe an o-ring glued to an old UV filter ring? 

There are no problems with the lens bumping except it may dent the glass. In effect there is a black ring inside the wet lens so if it goes metal on metal you can just put some tape on it or small silicon spacers

There are many lenses that do not offer the full zoom range on the port chart the tamron is not an exception some lenses even only work at a single focal length

[BobbyV 8]

I have nothing against the 28-60, but the 28-75/2.8 is a far more useful topside lens (one that I would actually opt to use). I had the G1 version which was exceptional.

Does the Tamron lens have better characteristics for UW use compared to the 20-70/4 G? That lens would seem to provide the option for dome port use for semi-wide rectilinear shots in addition to the UWA with WAPC. But I'm green to underwater optics so could be missing something about the lens design. 

[Phil Rudin 485]

I can give you an educated guess. With the New Tamron 28-7mm G II you get a zoom range from 28 to 56/57 with no vignette on the wide end and bumping the WACP-1 on the long end. With the older 28-75 it was more like 28-40 or so. With the new 28-75 the lens extends about 30/31mm. With the 20-70 F/4 from 28-70 the lens extends about 60mm so the zoom range would be about half on what it would be with 28-75 or around 28 to 40/42 again this is just a guess but will be in the ball park. With the 20 to 70 you will deal with vignetting on the short end and bumping the WACP-1 on the extended end. Also with all of these lenses sharp focus will start around eight inches (around 20cm) from the WACP-1 glass. The 28-75mm G II will AF all the way to the WACP-1 glass and be quite sharp in the center but it falls off quickly as you move towards the edges shooting in the F/8-F/9 range, this is both at 28mm and at 56/57. With the Sony 28-60 you can shoot the full range with the required extension which can also be used with the 28mm F/2. With the older Sony FE 28-70mm you need an extra 20mm of extension.  

Edited March 28 by Phil Rudin

[BobbyV 8]

Thanks @Phil Rudin the last point about the sharpness, are you suggesting the sharpness is more uniform across the frame with the 28-60 versus the 28-75 at F/8-F/9?

[Phil Rudin 485]

Both images are at 28mm and F/8, the leaf is within an inch of the WACP-1 glass and quite sharp at 200%. With the face mask if it were within an inch of the glass this image would look very soft in the eyes and around the rest of the image with only the mask skirt being in focus. I suspect this would be the case with most land lenses using a wet wide lens this close. 

 

[BobbyV 8]

Thanks. So I take it this is a case where CFWA is better served by a fisheye lens or EMWL despite the ability for close focus using the WACP and a rectilinear lens. 

[Phil Rudin 485]

No not really, this is more of a case of knowing how to best use the equipment you have. The results will very more based on the skill of the photographer than very like equipment. I have know experience with EMWL and a FF fisheye is usually 180 degrees V. 130 degrees V. a macro lens widened to as much as 160 degrees so hardly apples to apples.

 

[Interceptor121 843]

4 hours ago, BobbyV said:

Thanks @Phil Rudin the last point about the sharpness, are you suggesting the sharpness is more uniform across the frame with the 28-60 versus the 28-75 at F/8-F/9?

That is not what he said

When you are very close you have depth of field, field of curvature and other aberrations that are more prominent than when you focus away

in general wider lens closer to the subject