"New" hotshoe mounting for Red Dot Sight

Started Jul 8, 2017 | Discussions
Hatstand Senior Member • Posts: 1,619
"New" hotshoe mounting for Red Dot Sight

There have been many discussions on the use of Red Dot Sights here in the past, so I thought I'd share this...

The short version:

I came across THIS hotshoe mounting the other day, for Red Dot Sights.
Maybe it's old news, but personally I'd never seen this design before.
But anyway - as a long-time RDS user, I decided it was worth a try.

It duly arrived, I've been trying it out, and my verdict is:
Despite several shortcomings...
...I consider it the best currently-available mounting!

The long version:

My RDS usage
I've been using Red Dot Sights for airshow photography for many years now. I use one in place of a viewfinder, so I can watch the airshow with both eyes and a full field of view, while still taking photos. I hold the camera out, elbows tucked in and strap gently pulled taut against the back of my neck, to make a "tension tripod" for stability. I track planes using the red dot sight, as easy as pointing my finger. I use quick glances at the rear screen to check zoom.

When calibrating, I align the sight to a very distant object so it points pretty much parallel to the lens axis. This means it is always pointing at a spot a few inches above the target, regardless of distance. That might matter for insects and small birds... but a few inches too high on an object the size of a plane is of no consequence!

My choice of RDS type
Red dot sights are easy to buy, and there are many designs to choose from - you can get them from the likes of Amazon, or any airgun shop.

Personally, I favour THIS type of design: Compact, large mirror, thin mirror frame, "open" (not tube) design, good choice of colours/reticles/brightness. This gives the most versatility, the least obstructed view, and the widest range of angles you can look though it. (Consequently, I don't rate the Olympus EE-1 particularly highly in comparison...!)

Mounting an RDS to a camera
So gett8ing an RDS is the easy part, the problem is always mounting the RDS to your camera. Above all, I want:

  • A "repeatable" fit, so I only have to align the RDS once, no matter how many times I fit/remove it... and
  • No movement within the hotshoe, so it isn't easily knocked out of alignment.

I've tried various types of mount over the years, and I liked the early types of Photosolve Xtend-a-sight the best. I've still been using one the current Photosolve mounts until now...

The new mount design
The mount design above has a rather short rail, and it protrudes some way out of the back of the hotshoe, so it might (depending on your camera's hotshoe position), stick into your forehead when trying to use the EVF! O_o It is also comparitively slow to fit and remove compared to other designs.

BUT... so far it seems the most stable of all the currently-available mounts I've tried. No movement/swivelling within the hotshoe, even if bumped when handling. It has been retaining its alignment brilliantly. Fit/alignment is repeatable.

(Bear in mind though, hotshoes can vary quite a bit in size and shape, and manufacturing tolerances are probably a bit slack - so YMMV!)

Fitting the new mount
The major feature of this mount is, it has a pair of allen-keyed grub screws which you use to fix it in position in the hotshoe - unique to this design, as far as I know.

This not only stops the mount sliding out accidentally, or tilting vertically... it also seems very good at preventing swivelling within the hotshoe (which is a perennial problem for most RDS hotshoe mounts - the tiniest amount of swivelling can make a big difference for long focal lengths and distant subjects!)

I recommend to keep pushing the mounting into the hotshoe while tightening the screws. This (hopefully) prevents any gap at the end of the hotshoe, that might allow movement or swivelling. Be careful of over-tightening - the grub screws are small and I suspect threads might be easily damaged. It doesn't take much tightening at all to lock the mount in place.

Once the mount is fixed in the hotshoe, you mount your RDS onto the rails. There is a 20mm rail and a smaller dovetail rail which ought to accommodate most designs.

It's a bit of a nuisance to fit, but once it's done I'm set for a whole day at an airshow. So I can tolerate spending a minute or two to mount it.

Other notes
It occurs to me, that those brave enough, and skilled enough, and posessing the appopriate tools... could probably make small depressions or grooves in the top of the hotshoe, where the grub screws make contact. I imagine this could greatly increase the resistance to swivelling, while also reducing the tightening required for the grub screws.

The mount came with an allen key for tightening the grub screws - but it was too small and didn't work! I'm using a 1.5mm allen key of my own instead.

By the way, I bought mine in the UK from 365astronomy. It's the same design, despite the picture showing some differences (ie. their picture doesn't show a 20mm rail! But the one I received does have it!). It's bare metal though, instead of black...

sherman_levine
sherman_levine Forum Pro • Posts: 13,652
Re: "New" hotshoe mounting for Red Dot Sight

Clever product, particularly the rigid placement in the hotshoe. Thanks for the info.

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GeraldW Veteran Member • Posts: 8,859
Re: "New" hotshoe mounting for Red Dot Sight

First thing that came to me was the possibility of the locking screws damaging the hot shoe's dedicated contacts.  Is that a real possibility?

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Jerry

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OP Hatstand Senior Member • Posts: 1,619
Re: "New" hotshoe mounting for Red Dot Sight
1

GeraldW wrote:

First thing that came to me was the possibility of the locking screws damaging the hot shoe's dedicated contacts. Is that a real possibility?

No, the grub screws cannot touch the electrical contacts inside the hotshoe - only the tops of the hotshoe "guide rails".

Actually, when you tighten the screws, I think they're likely to pull the foot of the mounting up against the underside of the rails (if there's any gap) - so there's pretty much no chance of any pressure on the hotshoe contacts. (And the contacts are recessed anyway)

Mount locked into the hotshoe of a camera

The screws need very little tightening to work, and I can see no mark on the hotshoe guide rails where the screws touch. (Panasonic G80 micro-four-thirds camera).

So there seems little/no chance of damaging the hotshoe rails either. I think you'd probably strip the screw threads before the hotshoe could be damaged.

GeraldW Veteran Member • Posts: 8,859
Re: "New" hotshoe mounting for Red Dot Sight

Excellent!  I thought of the screws going in at 90 degrees to your image.  I have to get one of those!

Thanks.

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Tom K.
Tom K. Senior Member • Posts: 1,728
Re: "New" hotshoe mounting for Red Dot Sight

I'd like to see a few pictures of the RDS mounted with this mount. You mention that it sticks back from the top of the camera - if it blocks use of the EVF then it's not a good design.

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OP Hatstand Senior Member • Posts: 1,619
Re: "New" hotshoe mounting for Red Dot Sight

Tom K. wrote:

I'd like to see a few pictures of the RDS mounted with this mount. You mention that it sticks back from the top of the camera - if it blocks use of the EVF then it's not a good design.

Yes, it's a definite flaw in the design. Roughly half of it sits inside the hotshoe, and the other half sticks out. (ie. the amount that sticks out is roughly the length of a hotshoe).

I suspect they did it to reduce production costs - this way, they can use a single long extrusion, do all the required drilling from one direction... then just chop the extrusion up along its length, to make the individual parts. (Making the rails project forward would make the manufacturing more complicated and therefore more costly...)

Whether it's a problem or not, may depend on the position of your camera's hotshoe, and the type of RDS you use. FZ1000 might be completely OK, FZ300 less so... but either of them is likely to fare better than my G80...!

I suppose In theory, it could be shortened with a hacksaw - provided the RDS being used doesn't need much rail to mount securely. But I don't imagine that sort of DIY appeals to most people.

It's not a problem for my purposes, because I generally don't use the EVF for the flying displays at airshows. And although it's uncomfortable - I can still use it if I must (on my G80, it's actually the back of the RDS that causes me the most nuisance, rather than the back of the mount).

When I get home tonight, I'll try putting it on my FZ1000 - and take a photo or two to post here.

sherman_levine
sherman_levine Forum Pro • Posts: 13,652
Perhaps reshape it

Here's a 3D printed product which has a better shape, albeit without the grub screws. One could reshape the aluminum mount to in the same manner.

https://www.shapeways.com/product/SD6KGGVAJ/red-dot-to-hot-shoe-adapter?optionId=15967649

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OP Hatstand Senior Member • Posts: 1,619
Re: Perhaps reshape it

sherman_levine wrote:

Here's a 3D printed product which has a better shape, albeit without the grub screws. One could reshape the aluminum mount to in the same manner.

https://www.shapeways.com/product/SD6KGGVAJ/red-dot-to-hot-shoe-adapter?optionId=15967649

Not sure what you're suggesting to modify the aluminium mount...?

But I think that 3D-printed design could quite easily incorporate the "grub screws" idea!

Drill a couple of holes, tap the holes (add screw threads), insert a couple of grub screws... et voila?

Now I have to buy one and try it!

sherman_levine
sherman_levine Forum Pro • Posts: 13,652
Re: Perhaps reshape it
1

Hatstand wrote:

sherman_levine wrote:

Here's a 3D printed product which has a better shape, albeit without the grub screws. One could reshape the aluminum mount to in the same manner.

https://www.shapeways.com/product/SD6KGGVAJ/red-dot-to-hot-shoe-adapter?optionId=15967649

Not sure what you're suggesting to modify the aluminium mount...?

But I think that 3D-printed design could quite easily incorporate the "grub screws" idea!

Drill a couple of holes, tap the holes (add screw threads), insert a couple of grub screws... et voila?

Now I have to buy one and try it!

Thought you might do that. Just didn't know if you had the tools. The shapeways site has a lot of very interesting 3D printed items.

For the aluminium mount, if you trim off the bottom of the lower bar (the end which doesn't have the grub screws) you can then turn it 180 degrees so it doesn't poke you in the eye.

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OP Hatstand Senior Member • Posts: 1,619
Re: Perhaps reshape it

sherman_levine wrote:

Thought you might do that. Just didn't know if you had the tools.

Well, I don't have the right size tap... but I can get one for cheap

The shapeways site has a lot of very interesting 3D printed items.

Yes, I have poked about that site before, seeing what kind of things I might make, if I had my own 3D printer

I even remember seeing that red dot mount, but dismissed it at the time because there was no means of locking it into the hotshoe - not even a thumbwheel as seen on most designs.

But I am interested now! Because the grub screws from the other design have worked very well... and it looks like I could add those to this design fairly easily...

For the aluminium mount, if you trim off the bottom of the lower bar (the end which doesn't have the grub screws) you can then turn it 180 degrees so it doesn't poke you in the eye.

Ah yes, I see.

Unfortunately the part is small enough that it could be awkward to work with, yet big enough that manual filing etc could be very slow and tedious.

I imagine I'd have to make some custom jigs to use any power tools, or even just to manually file it down without messing it up. So, not really motivated to try it - especially given I don't have any real need for the modification, other than making it look nicer...!

Castaway
Castaway Veteran Member • Posts: 4,923
Re: "New" hotshoe mounting for Red Dot Sight

Hi Hatstand.

After reading this thread and Roger,s Post of swallows in flight on the Wildlife thread I decided to get out my old Red Dot, not used for years, and give it a try again.

I have the old Photosolve mount that fits fine in the FZ30 but but does not want to go into the FZ200 or FZ300 hot shoes so am thinking of filing it down a little, of course it would probably end up too slack.

I was also looking at the grub screw on the mount and it does not seem to make any effect on the mount. Is it supposed to widen the mount as it is tightened?  It seems to come to a stop without any effect. Maybe I have to force it.

Do you have any advice? I don't think that I want to be spending to much on a new mount as it would be something that I probably wouldn't use to much.

Thanks for any advise.

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OP Hatstand Senior Member • Posts: 1,619
Re: "New" hotshoe mounting for Red Dot Sight

Castaway wrote:

Hi Hatstand.

After reading this thread and Roger,s Post of swallows in flight on the Wildlife thread I decided to get out my old Red Dot, not used for years, and give it a try again.

I have the old Photosolve mount that fits fine in the FZ30 but but does not want to go into the FZ200 or FZ300 hot shoes so am thinking of filing it down a little, of course it would probably end up too slack.

I was also looking at the grub screw on the mount and it does not seem to make any effect on the mount. Is it supposed to widen the mount as it is tightened? It seems to come to a stop without any effect. Maybe I have to force it.

Do you have any advice? I don't think that I want to be spending to much on a new mount as it would be something that I probably wouldn't use to much.

Thanks for any advise.

Do you mean the original Xtend-a-sight that looks like picture below?

Original Xtend-a-sight

If yes, then screwing in the grub screw at the side, should push open the split - do this after inserting it into the hotshoe, to get a good tight fit, and lock it in place. Loosen the screw again, when you want to remove the Xtend-a-sight from the hotshoe.

NB. Make sure the red dot sight is fitted far enough forward on the mount - if it's fitted too far back, it will prevent the split part from opening up when you turn the grub screw.

If the mounting doesn't fit into your FZ200 or FZ300 hotshoes, perhaps you just need to loosen the grub screw? Or pinch the sides together while pushing it into the hotshoe? (with pliers if need be?) You shouldn't need to file it down...

OP Hatstand Senior Member • Posts: 1,619
Re: "New" hotshoe mounting for Red Dot Sight

Hatstand wrote:

When I get home tonight, I'll try putting it on my FZ1000 - and take a photo or two to post here.

Here's what it looks like on my FZ1000:

Maximum comfort, RDS is fitted well forward - still secure and stable

It's a tighter fit than on my G80. The mounting doesn't protrude beyond the eyecup, and in the photo above I've fitted the RDS well forward as well - so it's nowhere near my forehead, and EVF use is fully unrestricted.

But it's holding onto a pretty short section of the mounting rail... it still feels stable and secure, but perhaps not as resistant to knocks as it could be?

For my purposes, I'd push the RDS back until it touches my forehead when I use the EVF:

RDS fitted as far back as possible - more secure, but using the EVF a lot could get uncomfortable?

This way, the RDS is holding onto a longer section of the rail, about 1cm. That would work for me, because I rarely want to use the EVF while the RDS is fitted. But YMMV...

Castaway
Castaway Veteran Member • Posts: 4,923
Re: "New" hotshoe mounting for Red Dot Sight

Hatstand wrote:

Castaway wrote:

Hi Hatstand.

After reading this thread and Roger,s Post of swallows in flight on the Wildlife thread I decided to get out my old Red Dot, not used for years, and give it a try again.

I have the old Photosolve mount that fits fine in the FZ30 but but does not want to go into the FZ200 or FZ300 hot shoes so am thinking of filing it down a little, of course it would probably end up too slack.

I was also looking at the grub screw on the mount and it does not seem to make any effect on the mount. Is it supposed to widen the mount as it is tightened? It seems to come to a stop without any effect. Maybe I have to force it.

Do you have any advice? I don't think that I want to be spending to much on a new mount as it would be something that I probably wouldn't use to much.

Thanks for any advise.

Do you mean the original Xtend-a-sight that looks like picture below?

Original Xtend-a-sight

If yes, then screwing in the grub screw at the side, should push open the split - do this after inserting it into the hotshoe, to get a good tight fit, and lock it in place. Loosen the screw again, when you want to remove the Xtend-a-sight from the hotshoe.

NB. Make sure the red dot sight is fitted far enough forward on the mount - if it's fitted too far back, it will prevent the split part from opening up when you turn the grub screw.

If the mounting doesn't fit into your FZ200 or FZ300 hotshoes, perhaps you just need to loosen the grub screw? Or pinch the sides together while pushing it into the hotshoe? (with pliers if need be?) You shouldn't need to file it down...

Hi again. Thank you for your response. Yes that  is the Xtend-a-sight that I have. The grub screw seems to have little or no effect on the width of the hotshoe mounting though, even tightening it with pliers and measuring it with digital calipers.

In the end I did have to file it a little and it now fits in the FZ300 so will be giving it a try.

Thanks again.

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sherman_levine
sherman_levine Forum Pro • Posts: 13,652
Modification of the shapeways product

sherman_levine wrote:

Here's a 3D printed product which has a better shape, albeit without the grub screws. One could reshape the aluminum mount to in the same manner.

https://www.shapeways.com/product/SD6KGGVAJ/red-dot-to-hot-shoe-adapter?optionId=15967649

I received mine yesterday and drilled/tapped two holes for setscrews. I also shortened it slightly.

Easy project. Drill slowly, removing the drill often to cool so you drill (and don't melt) the plastic. ( I used a Dremel miniature drill press. )

Drill all the way through the mount so you can tap it.

Very happy with the result.

The item as received (top) and shortened with setscrews in place

The shortened mount fits completely in the RDS.  By shortening the mount, I could remove the RDS by loosening (but not removing) its two side screws and sliding it off the mount, so removal/replacement is fast and reproducible.

Bottom of RDS with mount fully inserted.

Side view of RDS mounted to permit use of FZ1000 eyepiece.  It could be moved backwards on the mount if you found it more convenient.

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OP Hatstand Senior Member • Posts: 1,619
Re: Modification of the shapeways product

sherman_levine wrote:

I received mine yesterday and drilled/tapped two holes for setscrews. I also shortened it slightly.

Easy project. Drill slowly, removing the drill often to cool so you drill (and don't melt) the plastic. ( I used a Dremel miniature drill press. )

Drill all the way through the mount so you can tap it.

Very happy with the result.

Nicely done!

Do the screws lock it in place well, in the hotshoe?

What size grub screws are those?

I don't understand the reason for drilling right through the foot of the mount? Don't you only need to go through the top/rail part?

I've also got one of those mounts now I have a Dremel and drill press too, and I expect to attempt the same modification sometime soon
But haven't bought a suitable tap yet, or the grub screws...

sherman_levine
sherman_levine Forum Pro • Posts: 13,652
Re: Modification of the shapeways product

Hatstand wrote:

sherman_levine wrote:

I received mine yesterday and drilled/tapped two holes for setscrews. I also shortened it slightly.

Easy project. Drill slowly, removing the drill often to cool so you drill (and don't melt) the plastic. ( I used a Dremel miniature drill press. )

Drill all the way through the mount so you can tap it.

Very happy with the result.

Nicely done!

Do the screws lock it in place well, in the hotshoe?

What size grub screws are those?

I don't understand the reason for drilling right through the foot of the mount? Don't you only need to go through the top/rail part?

I've also got one of those mounts now I have a Dremel and drill press too, and I expect to attempt the same modification sometime soon
But haven't bought a suitable tap yet, or the grub screws...

It's very solid even in a loose hotshoe.

The screws I used were size 6-32, although 4-40 would have been fine as well. They should be 1/8" or 3/16" long (no longer than the thickness of the upper bar) if you don't want them to protrude from the top. Depending on how you mount your sight the protrusion may or may not matter to you.

Why did I drill all the way through? The drill needs to be smaller than the screw and tap, so the screw won't fit anyplace you don't tap. The tap itself is typically tapered at the end so you'll need to go entirely through the material (or at least drill and tap deeper than the screw length). Taps which are cut to fit the bottom of a hole do exist, but they're not what you'll generally find in the hardware store.

The screws will work fine as long as even part of the screw crosses the slot and touches the hot shoe. You don't need the entire screw crossing the slot, so you can stay a bit farther from the edge.

Each tap requires a specific drill size, so be sure you have that on hand before you start. Test on scrap first. Also make sure you have a hex key suitable for the screw.

Typical tap with tapered tip.

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OP Hatstand Senior Member • Posts: 1,619
Re: Modification of the shapeways product

Thanks for the detail Sherm.

I've never tapped anything this small before, so didn't realise the length of taper at the end of the tap would be an issue...

Viking9
Viking9 Senior Member • Posts: 2,617
Anyone got any fast jet photos using RDS?

Anyone got any photos of fast jets (going fast) taken with a camera using a RDS?

Tom

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