If you have one of those square rubber sheets used to grip stuck lids, you might try that.

100 % agree! Before I traveled to Wyoming for the 2017 eclipse, I practiced with my setup on the morning and afternoon sun, using the same filter I'd be using for the "event." I experimented with various ISO, Aperture and shutter speeds (based on various "pro recommendations" to find the combo I was happy with. I even "pretended" to take the filter off and see how fast I could run through the different shutter speeds during totality. By the time it was game day, I pretty much had my routine committed to memory and was able to get all the shots I needed from start to finish without really having to think about it. I plan to practice again before April.

Yes, it is on the pricey side and there are definitely more cost efficient options.

Actually that's not correct. The Firecrest Filter I used was 18 Stops. It is a filter made specifically for photographing solar eclipses, which is why it's called "Firecrest Ultra Neutral Density (IRND) Solar Eclipse Filter". The filters are available also in 20, 22 and 24 stops. You're confusing Optical Density Number with Stops of Light. A filter with an Optical Density Number of 5.4 is an 18-stop filter.

Also the reason the sun is white with this filter is simply because that is the actual color of the sun. Like any quality ND filter, this filter does not add any color cast to the image as many cheaper filters do. If you use this filter and want a yellow or orange cast, that can always be added in post.

Yes, the camera will still operate fine with a dead internal battery. I’ve seen discussions about it only being changeable by a technician. I was just hoping someone might have figured out the procedure they could share. Not a big deal, but if it wasn’t terribly difficult I’d like to install a new one. If not, it’s not the end of the world.

I’m posting this here since it is regarding a Canon T70 film camera that I’ve owned since new in 1984. In addition to power provided by two AA batteries, there is also apparently a lithium battery internal to the camera that is used to power storage of user settings. The battery is said to last about 5 years so I’m 99 % sure mine is long dead.

The good news is, the camera will operate fine without the ability to store settings, but it would be nice to have all functionality.

Question…does anyone know how to change the lithium battery in this camera (it is supposed to involve some disassembly). Or, if you don’t know how, do you know any vintage camera repair places who could do it?

This is the filter I used for the 2017 eclipse, and plan to use for this one too. Note it doesn’t provide any artificial tint, so the colour will be white, as the sun really is. However you can add tint to taste in post.
https://formatt-hitechusa.com/products/firecrest-ultra-neutral-density-irnd-solar-eclipse-filter?variant=43967731826937

Like I said, my experience with my LX100 makes me appreciate the appeal. In fact, not just for the retro looks but also the amazing capabilities, I’ve been drooling over the new Fuji X100VI.

Actually, Canon's move away from that "certain look" started with the T50 in 1983. SLR sales had been declining for the past few years and Canon decided that a more modern look with more automation was the answer. The T50 was an SLR but it only had one program mode and had to be manually rewound, so it was really more of a beginner's point and shoot camera with interchangeable lenses. Realizing they needed to give more control for serious photographers, they released the T-70 in 1984. The T-70 was the first Canon camera (maybe the first SLR?) to have an LCD screen to display setting information. The T-70 had several different modes, including a Tv mode where you could choose the shutter speed and, assuming the aperture ring on the lens was set to auto, the camera would chose the Aperture. According to Wikipedia, a Popular Science reviewer, the T-70 "could be too good for amateurs." (I wonder what that reviewer would say about today's DSLRs with multiple couples menu systems).

As it happens, my first serious SLR camera was the T-70. Up till then, I'd only had cheap point and shoot cameras that use, I think, 120 film. I never owned any of the SLR cameras with that "certain look." I had been stationed (air Force) on a remote mountaintop site in Greece in 1984. One day, while at the BX at our main base, Hellenikon Air Base, in Athens, I just happened to see a display full of cameras. Kind of on the spur of the moment, I thought that getting a "real" camera with interchangeable lenses and learning "real" photography would be a great way to fight the boredom of living on a remote mountaintop for 2 years. Not really knowing what I was looking for, and after some discussion with the sales representative, I ended up getting the T-70. I liked that it had a lot of automation, while still providing a lot of control over the settings. It looked more modern than the other cameras with all their dials and cranks. Being a bit of a gadget geek (engineer and former large mainframe computer technician), the LCD screen and automatic features appealed to me at the time. I still own and shoot with my T-70.

The T-90 came out a couple years later and took the already cool automated features of the T-70 to the next level. There was also a T80 a year after the T70 which was the first (and only) FD-mount camera with auto-focus. However, you could only use AF with a few lenses specifically made for the T80. Other FD lenses would work, but only as manual focus. Interestingly, Canon also sold a T60 (they sold it but didn't make it) which actually came out after the T90 but, while it had that T-series look, it was a fully manual camera, with manual everything.

But speaking of retro, fast forward to today - in addition to my R5, I also have a Panasonic "retro" LX100. This little camera is a real gem to use. It has mechanical dials on top to set shutter speed and exposure compensation, as well as a retro style ring on the lens to set aperture. Both shutter speed and aperture can be set to an auto setting to give you Av or Tv modes, in addition to many auto modes. There is something about having the tactile feel of those dials and switches that just adds to the enjoyment of using that little camera. Based on my experience with this little camera, I can sort of understand the appeal of some of those retro cameras.

My Sigma AF is not bad. I suspect (without proof) the differences are due more to the much newer and better focus motors in today’s RF lenses

You make a compelling case for the RF100-500.

Money isn’t a problem per se, but I just set a limit for myself not to spend over $2,000 (additional out of pocket). Your assumption is correct that this will be mainly for birds and to a lesser extent general wild life. As I mentioned in another reply, the Sigma is good but I’m sure the keeper rate would be better with one of the RF mounts.
My current gear (for birds) is the R5 with the Sigma 150-600.

Well, probably the main thing is, while it does take sharp pictures, I find that the keeper rate isn’t what you would call super high. I have heard that the RF lenses are much better at auto focus and tracking. So I don’t know if I would call that a shortfall, but it would be nice to have a better keeper rate when I’m shooting for example, birds in flight.

Weight is another factor, though less important. The sigma lens is not super heavy but it’s also not super light. I can handhold it but it does get tiring after a while. Of course, the 200–800 would be even worse in this regard.

Thanks for the links. I actually had already watched the Jan Wegener comparison of the 100-500 vs 200-800.

When you say if you were to make the choice today, do you mean you'd get the RF200-800 instead of the RF100-500? My biggest hesitation with the RF200-800 is the small aperture. If I sold the Sigma for the RF100-500, I'd only be giving up a 1/3 stop but also be giving up 100mm of reach. If f/7.1 is a handicap, I can only imagine f/9 is a much bigger handicap. I like to shoot birds at the Bosque Del Apache and some of the best shots occur in sunrise or sunset conditions. I'm wondering how high I'd have to crank the ISO to compensate.