cerich

2 hours ago, ChrisH said:

Correct, the neoprene dome cover can damage the glass! If you take the cover with you on a dive, it is soaked with salt water. Attaching it to the dome port, the salt water will dry on the glass and can cause damage to it.

 

What you can do is using two port covers: one for protection during handling the camera for diving and another one that stays dry and is only used after the dive.

Otherwise you can keep the neoprene cover and the dome wet if there is no chance to rinse it properly (maybe between two tank dives), because the salt water will only damage the glass if it dries on it.  As long as it is wet, it is not a problem.

 

So yes, don't leave your neoprene cover on the dome after the dive, if it dries ist can cause damage!

on the mohs hardness scale.. salt is 2.5, glass 5.5-6. Salt won't scratch glass other than really long term erosions with some energy behind it. It can however scratch coatings that aren't designed or choosen for a high mohs rating. You can get coatings between 6-8 fairly easily and I would hope most glass domes the manufs are doing that... but YMMV.

That said, keeping a done wet until after rinsed and then dry it properly is important but I worry more about staining than scratches with glass ports. From a technique POV you gave good advice

33 minutes ago, Muellema said:

Hi,

 

Just to clarify my post. I removed watermarks wihtin approx. 15-30min. I never use tools, always just a linnen cloth polishing by hands. I`m not talkin on repairing deep skratches. But slight scratches on the glass are also possible to be polished within less than 1 hour by hand.

 

VG Markus

indeed, my post was to inform that the common thinking that any scratch on a glass dome is a done deal is not true always.

For water marks, much easier to fix. 

6 hours ago, Muellema said:

Hi,

I have used cerium oxide many times to remove watermark`s and even to polish small scratches at my glass ports. For me it works perfect.

Br Markus

same, even used it a full day once and fine git sandpaper to rectify a pretty bad scratch in a glass dome one. That said, It's major work, requires power tools (drill with sandpaper on discs, 1500, 2000 then 3000 and a bench buffer for the cerium oxide polish stage first with 2.3 microns then with 1.2 microns). It is "doable" but had I been anywhere close to where could send it for new glass, I would have. Is it as optically as good or strong? Nope, but you can't see the scratch in images, no distortion I can discern and it didn't implode at 180 ft so.. there is that. You aren't going to get much results without power tools, just saying, or be there a week for scratch, for the stains, yeah but use elbow grease (or at least a dremel with appropriate bits

It also occurred to me, after I was done, that there are actual businesses in almost everywhere that polish glass for glasses on face and other stuff like construction on the daily and it was likely could find someone willing to give it a go with better tools and are used to polishing glass and I should have tried finding one to give it a go first



 

On 2/28/2024 at 6:02 PM, Troporobo said:

Close focus wide angle is something I’ve been wanting to gear up for a long time now.  With an impending move to a great wide angle locale but an enduring obsession with macro photography, now is the time.

 

Disclaimer: I shoot with the Olympus EM-1 mk II and will keep it until OM Systems comes out with something significantly improved.  I’m not interested in moving to another format even if it would guarantee production of regular contest winners.  I use the camera on land and travel frequently and so the size and weight are optimal for me.  
 

Ideally the new setup will perform well at both CFWA and reef scenic.  I do not anticipate using it much for blue water pelagics.  I understand my options as follows. 
 

(1) I have the excellent Olympus 7-14mm f2.8 Pro lens and could put it behind a 170mm dome.  I haven’t been able to find out how close this will focus so unsure of potential for CFWA.  That dome might also work for the 12-40mm lens although that’s not a focal range I’d use often.  

 

(2) The Panasonic 8mm f3.5 FE or the reportedly excellent Olympus 8mm f1.8 Pro lenses can be housed behind either a 4.33” or 140 mm dome, but I haven’t found info about the advantages of one vs the other.  I have read that either will focus right at the glass of the smaller dome for CFWA but don’t know how one or the other fare at traditional WA or behind the larger dome.

 

(3) Adapt the excellent Canon 8-15mm FE behind a 4.33” port as suggested by Alex Mustard in comments to one of his recent videos.  Same questions as #2

 

(4) FWIW I have tried the Panasonic 7-14 behind a 150mm dome and it will neither focus closely nor produce acceptable edges.  It’s Ok for scenarios like blue water pelagics where the edges are not critical. 

 

Im leaning toward a FE and small port despite my unfounded bias against fisheye distortion.  OK, I’m ready for your thoughts!  TIA

 

 

ignore my earlier post, see you went different direction

Saw this on ebay, looks like a pawn shop is selling off a bunch of albums full of UW images in E6.

I clicked on one and took a look, just curious..and it caught my eye. Seals caught in nets. Then I started clicking thru and I realized whoever it was that took these pictures was very, very good.

There are 13 lots of 300, I saved them in my watch list and got an offer of $50 a set, and darn if I am not slightly temped. This stuff could make a book, and I still have no clue who it is. Whoever it is 

Here is a link to the guy selling, you can click in and enjoy. It's really quite something, for those that have never shot 35mm, these images are truly the work of someone very good.

Store on Ebay with the slide collections
 

It truly looks like a pretty special lens. 

https://phillipreeve.net/blog/review-laowa-10mm-2-8-af-the-beginning-of-a-new-era/?fbclid=IwAR2pYdcHaDj1zGb97Xz-GoBuAgD82qrv2AWHxaEn9WYQi9kXCpWKghJkZy8

Chris Richardson, I have been shooting UW on and off since the late 80's and full time in dive industry since 95. Currently on sabbatical having decided to take on some side projects and my partner at Deep 6 (Deep 6 About us) running the show daily now after me doing for the first 7 years. 

Well done to those that have started this up and wish all success