Continuously illuminate focus point?

[beryllium10]

Does anyone know if it's possible to keep a focus point in the D810 viewfinder continuously lit? 

I just tried to photograph the International Space Station.  Unusually for this time of year we have a cloudless night sky in Seattle, and the ISS has been making bright passes.  It moves quickly across the sky and would be easier to track steadily if I had an illuminated focus point in the viewfinder.  I'm not trying to acquire focus on the ISS - I've set focus on the moon - but tracking would be easier with a visual reference point in the finder.  Menu item a6 lets me light up my selected focus point briefly as I press the shutter, but doesn't give me the option of continuous illumination.

[Frank Fremerey]

menu a5 focus point illumination = ON

continuous seems to be an option for manual focus only

[Akira]

menu a5 focus point illumination = ON

continuous seems to be an option for manual focus only

On D750, the focus point will lit only briefly when the shutter button is half-pressed, as described by John.

John, how about using a dot sight like Olympus EE-1 which can be mounted on the hotshoe, although it is pricy:

http://www.getolympus.com/ca/en/ee-1-dot-sight.html

[Frank Fremerey]

On D750, the focus point will lit only briefly when the shutter button is half-pressed, as described by John.

John, how about using a dot sight like Olympus EE-1 which can be mounted on the hotshoe, although it is pricy:

http://www.getolympus.com/ca/en/ee-1-dot-sight.html

manual D810:

[beryllium10]

Frank, thanks for responding, but those settings do not illuminate the point continuously.  Even with a5 set to Focus point display>Manual focus mode>ON and a6 set to Focus point illumination>ON, and the camera in manual focus mode, the focus point will only illuminate for a moment when the shutter is pressed half-way.  It seems that, by 'Focus point illumination', Nikon means momentary illumination.

Akira, thanks for the suggestion, I had not thought of a dot sight.  Looking at your link, the EE-1 sight is described as 'Perfect for super telephoto shots of wildlife', so presumably has a fairly high optical power.  That's what I need, as I'm trying to take the photo with a 300 mm lens and 1.4x teleconverter.  I wonder if I can rent one somehow, as I'm not planning to make a long-term hobby of photographing fast-moving objects in the dark!

I did discover that setting the drive mode to CH helped (with a5 and a6 as above), by flashing the focus point several times per second.

Cheers,  John

[Akira]

manual D810:

Frank, thank you for the copy of the manual.  According to John, the behavior of the illumination seems to be the same as on D750, though.  With the function "on", the focus point is only "displayed" continuously, but "illuminated" only when the shutter button is half-pressed.  I guess Nikon's terminology is confusing.  My manual is in Japanese, but its translation into English seems to be "correct" including the confusing terminology.   

John, glad to be of any help!

[Øivind Tøien]

Frank, thanks for responding, but those settings do not illuminate the point continuously.  Even with a5 set to Focus point display>Manual focus mode>ON and a6 set to Focus point illumination>ON, and the camera in manual focus mode, the focus point will only illuminate for a moment when the shutter is pressed half-way.  It seems that, by 'Focus point illumination', Nikon means momentary illumination.

Akira, thanks for the suggestion, I had not thought of a dot sight.  Looking at your link, the EE-1 sight is described as 'Perfect for super telephoto shots of wildlife', so presumably has a fairly high optical power.  That's what I need, as I'm trying to take the photo with a 300 mm lens and 1.4x teleconverter.  I wonder if I can rent one somehow, as I'm not planning to make a long-term hobby of photographing fast-moving objects in the dark!

I did discover that setting the drive mode to CH helped (with a5 and a6 as above), by flashing the focus point several times per second.

Cheers,  John

Usually, the open dot sights do not magnify at all. There is just a semi-transparent mirror that projects the dot into the field of view in a way that makes its alignment to the target independent of the position of the eye. I have no specific knowledge of the Olympus version though. I got mine off ebay for much less funds. It is a great help aiming my 300mm PF  towards deep space targets. (Generally when I use the optical viewfinder I find that I anyway have to wait until camera automatically turns off as the viewfinder numbers are way to bright to see anything. An illuminated focus point would not be much help, just prevent me to see my target). I do need to fine adjust alignment by nudging the sight before each use as the fit to the camera hot shoe is not precise enough for the sideways alignment.

[beryllium10]

Øivind  -  Thanks for the information about dot sights, it sounds as though I should find a cheap one and see how it helps.  For my current project, the space station is so bright that the red illumination of the active focus point isn't distracting at all.  Just a reference point in an otherwise large, dark, field, which is what the dot sight would also do.  I'll look for a cheap one on e-bay.   

I could also use one as you do, for astrophotography.  I have a cheap star tracker, but when using it in the southern hemisphere without a pole star I had a hard time getting it aligned.  A dot sight would help a lot with the initial set-up.

Cheers,    John

[Øivind Tøien]

John, I never use the sight for polar alignment, just aiming at the target. I made the hot shoe attachment in a hurry from a plastic plate and the shoe of an old strobe.

As I seldom use the collar of the lens, usually aiming high and the camera plate gives adequate balance with the lightweight 300PF, I have lately seen an example where someone attached the sight to the plate of the unused lens collar, foot in top position. It would add the cost of of a dedicated clamp, which likely would be much more than  the $18 the sight cost me off ebay. May be I should look for a really small and cheap clamp. (It would take out one extra step of the procedure, although I usually do the alignment of the sight when focusing with my Bahtinov mask on a bright star.)

For polar alignment, proper leveling of the tripod, using a compass with correction for deviation in magnetic north applied and then move the altitude from zero to that of my latitude usually gets me the polar star within or very close within the field of the polar scope. It sure sounds trickier without the polar star in the southern sky though; if I recall your introduction, that would be Antarctica?

Edit: Found ebay link for sight from seller I bought from: https://www.ebay.ca/itm/Optics-Compact-Reflex-Red-Green-Dot-Sight-Scope-4-Reticle-for-Hunting-HY/172566776254?hash=item282dc809be:g:cG0AAOSwA3dYRhu-

Edit2: Just checked ebay for clamps - there were quite some offerings from $7 and up. I never thought about that before, was more oriented at the price level of the RRS clamps of my tripod heads, which is completely unnecessary here. I think I need to try this out.

Anyone here have experience if these cheap offerings are worth it (given my potential minimal application of holding a 50 gram device) ? If it is going to work it would of course still need to provide a precise firm fit.

One would still need to add the aluminum piece/rail that goes between (replacing my plastic plate), either commercial or machine something. (More ebay searching needed.)

Edit3: After some more searching on ebay, before I knew it,  I got myself a 50mm clamp and a 2" long rail for a total of $12.40 shipped.    It will take a while until it arrives so that I can see how this experiment works out. BTW I came across many even better offerings for the sight, although I did not check into shipping costs. (Need to watch out, the cheapest looking clamp had a deceptive $25 shipping cost when looking into it...).

[Øivind Tøien]

Just a note that the clamp and rail for my red dot sight arrived and is described and tested  here, http://nikongear.net/revival/index.php/topic,7555.0.html .

I am looking forward to try it on the night sky once it gets darker. I have high hopes that the on-site calibration step for the red dot sight can be omitted with this solution.

[Netr]

How will you know where the red dot is, when you aim at the sky?

[Øivind Tøien]

How will you know where the red dot is, when you aim at the sky?

This is not the type of red dot laser sight you see in the movies, where someone discover a red dot on their chest before things go bad. It contains a half transparent concave/curved  mirror that reflects back a virtual image of the dot in the line of sight and is mostly independent of horizontal/vertical position of the eye.The red dot light does not pass beyond the mirror. My model not only provides a red dot but can be switched to green and offers various shapes like a cross, a cross with a circle around etc. but I prefer the red dot at minimum intensity setting for astrophotography use.

There are some that use intense laser pointers for aiming in astrophotography, but they can be a concern to aircrafts and are illegal in many countries. I tried out a green one of the lowest intensity I could find on ebay, but it was very sensitive to cold and stopped working after a few minutes even with insulated batteries. (The temperature acts directly on the laser emitter).

[Erik Lund]

A short introduction can be found on Wiki:


https://en.wikipedia.org/wiki/Red_dot_sight

[Øivind Tøien]

Thanks for providing the link.

[beryllium10]

Øivind,  Thanks for extending this thread.  I think a red dot sight would indeed be useful for getting close to polar alignment in the southern hemisphere.  My recollection is that it was difficult to adjust from viewing the stars with the naked eye to the magnified (and reversed) view through the sight on the star tracker.  With a dot sight to get you fairly close to alignment, it should be much easier to do the final adjustment through the star tracker's sight.  So far no luck on finding a place that will rent me a dot sight to try out, but I'll keep looking, and will be following your post about your own set-up with interest. 

By the way, my southern hemisphere star photography was in central Australia, during a trip across the continent in August 2016.  The sky over central Australia on a cold winter night is often dramatic, so I bought the star tracker for the trip.  I've spent some time in Antarctica in the southern summer, but never wintered over and seen the Antarctic night sky. 

Cheers, John