Astro Photography Tips and a Benro Polaris Star Tracker Review

I purchased a Benro Polaris star tracker last year.

After many days of problems in the field I can tell you the pros and cons. Some of what I have to say in this post pertains to any star tracker. Some is Benro specific.

When writing this post, a four-year review from Dan Zafra on the Benro popped up in my inbox. Much but not all of of what I was going to say, he says in an excellent video.

My con list is much greater than this. One of the reason pertains to camera models. Zafra shoots on a Sony. Canon and Nikon owners will have a lot more issues.

Those issues all have work arounds, found by trial and error costing me many lost nights of photography. I also have better answers for some problems Zafra discusses in his full Benro Polaris Master Course.

If after reading this post, if you decide the Benro is for you, buy Zafra’s course. It will save you more hours than I can explain.

First here’s Zafra’s review, followed by my comments.

The Pros

• Less weight.
• Easy double tracking, unattended if you like.
• Once you get this thing to work, in the field, you will love it.

The Cons

• Poor support
• Terrible interface for Canon and Nikon
• Cost
• Steep learning curve

Zafra did not point out all of the Canon and Nikon issues. I can, with great frustration, and many lost nights in the field.

I have an EOS R-5. Here’s my take. I also go over a few things in more detail than Zafra’s course.

Canon and Nikon Issues

• You need an HDMI Cable for live view on your camera to work
• Benro does not provide this cable. Benro even stopped selling them. You are immediately on your own and you very much need this cable. Finding one that does work was trial and error.
• Without that cable, you will not have live view in your camera.
• The “Live View” button in the app is for Sony and will mess things up for Canon or Nikon viewers.
• To get to live view when using a Canon or Nikon, you need to click on “Shutter Mode” in the app.
• That’s when other issues crop up.

The HDMI Cable

You need a micro-to-mini HDMI cable. It needs to be a high end cable, but not too high end. A lightning or thunderbolt cable is too high end. It won’t work.

Benro not only fails to provide this HDMI cable on purchase, it stopped selling them altogether.

You will also need a Benro to USB-C camera cable. I did not get one with my purchase. I think I was supposed to. At least Benro sells these. I found an alternate that does work.

If you are a Canon or Nikon user, don’t bother trying to use this system until you get an HDMI cable that works.

This may sound silly but it took me two weeks, just getting the cables to work.

Connecting the Cables

I recommend connecting the HDMI and camera cables before you put the camera on the Benro.

The HDMI has an orientation that is hard to see and work with when you are looking upside-down with the camera mounted on the Benro.

Shutter Mode

Unlike Sony users, Canon and Nikon users will have to learn how to navigate between “USB Mode” and “Shutter Mode” to get to live view on your camera.

“USB Mode” would be better labeled “App Mode” and “Shutter Mode” would be what a normal person would call “Camera Mode”

On the Benro appp, there is an option to turn on “Live View”. Don’t do that! It sounds like what you want, but whatever the hell that is is for, it will mess up Canon users. I suspect but don’t know, Nikon users don’t want to mess with option either.

After clicking shutter mode, click on “complete” and you will see a live view in your camera.

Do your polar alignment here. Navigate to Polaris or better yet a bright star like Antares.

I have a grid mode set on my camera. Simply align Polaris, Antares, or whatever your “go to” star was in the middle of the grid and press OK. This won’t be sufficient for deep star objects and long lenses, or extremely long tracking times, but for normal wide-angle setups, perfection is overkill.

On the app, these “go to” stars shift position in the app based on what’s visible in the sky. Polaris constantly shifts, another annoyance. So, don’t just press the last location you hit.

My recommendation for Benro would be to fix Polaris in the first position, always, with bright stars like Antares for the summer milky way and Rigel and Betelgeuse (in Orion) for the Winter Milky way next.

One does not have to align to Polaris and it is much easier focusing on a bright star.

On Canon, focus in Shutter Mode. I focus three times. First roughly, then 6X, then 15X. Don’t count on that first rough view.

Now you need to take a test shot. Do not click your camera shutter. Instead, go back to USB Mode and take the shot with the app. If you take a test shot with your camera, the app my stop functioning.

Here’s the work around I discovered, too late. I was stuck one evening, unable to take images and gave up. I closed the app on my phone and was ready to pack up. For whatever reason, I turned the app back on, and was able to use the app to take pictures.

Procedure for Canon and Nikon

• Switch to Shutter Mode
• Focus
• Switch Back to USB mode (See Further Complication below)
• Take Shot
• Switch Back to Shutter Mode to review, zoom in to check tracking. You did remember to turn on tracking didn’t you?

Further Complication

As soon as you switch to Shutter Mode you will get a message “Please connect to your camera”

That message will be right over the spot you need to click to get back to USB mode.

Here’s what to do. Click on the green help button on the extreme right of the app.

That will pop up an even bigger overlay. Click somewhere on a normal part of the app screen.

Then you will see the button that lets you switch back to USB Mode.

Sony users do not have these issues. Zafra needs to add another lesson in his Benro course to cover these things.

Complications – All Camera Models

In addition to the camera-specific issues, there are a few big problems that can arise.

1. Alignment is 180 degrees off (pointing South)
2. Extremely slow (as in unusable) ability to control the Benro with joysticks.
3. Alignment is pointing North but negative (camera tilted down)

Zafra goes over points one and three in his course, but incompletely. He did not discuss number 2.

Alignment 180 Degrees Off

The main cause of issue number one is not pointing your phone in the proper direction for alignment.

So do it properly and realign.

Battery Issues

Battery interference can also cause the 180 degrees off problem. On one trip I had two external batteries, one to my camera and one powering the Benro.

I think those batteries influenced my iPhone. And if this happens, it’s not just a matter of rotating the app so that North is North. The app will never be happy. Trust me, I spent hours on this in the field. When I removed the external batteries the problem went away.

So the moral of this story is if you are using external batteries, get your alignment done first.

The Benro itself has a decent battery. Canon batteries drain fast. If you are out in the field for a long time you will need to change batteries or have a battery backup.

If you are doing H-Alpha images, discussed below, make sure you start with a fresh battery.

Please note that when you change batteries or turn your camera off then on, focus can shift. My 20MM f1.4 is particularly problematic despite the fact that the settings in my camera is set to off for “retract lens at power off”. I believe all Canon VCF lenses will have this issue.

Refocus if you turn your camera off for any reason. It’s just another thing to remember to check.

Extremely slow (as in unusable) ability to control the Benro with joysticks

I had this issue that Zafra did not mention.

The cause was a mobile hotspot turned on my iPhone. At home, testing, I had no issue because I had a strong WiFi signal. In the field, I was in a spot in Zion with one bar. I believe the app was trying to connect to the hotspot instead of forcing Bluetooth.

A loose connection on your “extra cable” (yes that’s the official name of it) might potentially cause a connection issue as well. Make sure the extra cable fully clicks in.

Buy a spare. That is the third cable you need. Have spares of all the cables.

Alignment is pointing North but negative (camera tilted down)

I believe the most likely culprit here is camera mounted on the Benro backwards.

Zafra describes a procedure of turning off everything, including the phone, restarting the phone and app.

Well guess what. That won’t help if your camera is on the Benro backwards. And it will cost you a lot of time too.

The iPhone Case

Zafra recommends removing the phone case for polar alignment. I suggest not doing this unless you need to.

I have a difficult time removing the case and getting it back on. But when I hit problem three I tried Zafra’s work around. It failed. My camera still pointed down. Why? My camera was mounted backward.

In my struggle to remove the case, I accidentally put my iPhone in vibrate mode. My wife who was out of town knew I was out for night photography. When she could not get a hold of me the next day, she almost sent the neighbor over to look for me.

I suggest not removing the case because the phone only gives a rough alignment anyway. You will still need to make a proper alignment with the app. So who cares if alignment without the case is slightly better than with it, because you will need to make adjustments anyway.

If you have a magnet on the back of your phone that does totally mess things up, then remove the case. Otherwise, it’s a waste of time that may end up getting your neighbor checking in to see where you are.

Using an L-Bracket

Zafra uses a lens collar to rotate between vertical and horizontal . I strongly prefer using L-Brackets.

But most L-Brackets block the cables. I bought an L-Bracket extension. It was clumsy. Not only clumsy, but it still did not provide adequate cable clearance.

L-Bracket lovers, there is a solution. I like it so well that I bought two. One is for my astro-modified camera, the other is for my regular camera.

The best L-Bracket for astro and even general purpose for Canon Users is the ProMediaGear PLXT3 Series

It solves two problems. First, the offset gives full articulation of your camera screen! So if your main objection to L-Brackets is screen articulation, consider the problem solved.

Second, it uncovers the cable connection hookups, a Benro necessity.

And as an added bonus, the nature of the bracket itself provides a nice handle for short-term carries.

PLXT3

You can see I have used that camera a lot.

The offset bracket gives full articulation of the screen and uncovers the cable connections.

The bracket itself makes a very convenient handle. It’s way more comfortable that it may appear above. But you do need another piece.

Benro designed the Polaris for horizontal images. Almost always you want to be in vertical mode. However, it’s possible you want to do a vertical stack of horizontal images.

This piece below, a Really Right Stuff B2 FABN-E fits on the Benro and allows the Benro to work in vertical mode.

Benro Setup

This image shows my Benro setup. This is what things should look like properly setup, almost.

The critical piece is the camera is point the right direction. You can see the RRS adapter, my L-Bracket, and the cables. If that’s not the view you see when facing your camera screen, Benro is going to point your camera down, not up.

There is a small error in the above image, purposely. I doubt it matters much for wide-angle photography, but the camera is not centered properly on the Benro. The lens should be centered directly over the Benro. Loosen the screw on the RRS clamp and center the camera.

One more tip. The RRS adapter need to be oriented so that the screw knob points out. Otherwise the cables will interfere with the screw knob.

Cable Wrapping Issue

If you use an external battery pack and are taking 180 degree panos, at the end of a set of shots, the Benro will go back to the staring position the fastest way.

After three sets of images my external battery cable was coiled tightly around my tripod. One more set of images would have either broken the cable or ripped the battery out of my camera.

To fix this issue, Benro needs to return to home the same way it got there, not going in circles wrapping cables around the Benro and tripod.

After nearly having a disaster with this, I use batteries. Change batteries after you finish a set. But if you are a Canon user (possibly any user), refocus the lens after changing batteries.

Anything Else?

Of course there is, otherwise I would not be asking.

I like to use, and recommend a leveling base, sometimes called a half-ball head. I use a Sunway Foto LB68 Leveling Base. It’s my normal setup, unrelated to astro. It makes leveling a tripod easy.

The above image is the model I recommend. I have an LB-68. The difference is the R-version has a rotating top. You can level the base, attach the Benro, then rotate the setup pointing reasonably North for a good starting point.

Instead of fiddling with tripod legs, a simple operation lets you level everything, then you can spin the setup where you want, but then you will have to remember to tighten the clamp so you do not accidentally spin it.

Here’s the catch. A leveling base interferes with the Benro. Some tripods may interfere as well. It depends on how wide the tripod is at the top.

To get around this problem you need an adapter.

Hooray, Benro offers a Benro Polaris Spacer and it works. It’s in my “Benro Setup” picture above. There are cheaper brands and I suspect they work just fine, but I have not tried them.

Skipped Images

Bento lets you set an interval between shots. The default is 5 seconds. It is not sufficient for my Canon. I think 5 seconds should be sufficient but it isn’t, and I have a fast card. I have on many occasions lost images. It’s a communication issue of some sort.

I have since discovered 7 seconds may not be enough. I am now set to 9 seconds. And there is another gotcha here. Even if you set the Benro to 7 or 9 seconds in Pro mode, the Benro will revert to 5 seconds when you start taking pictures.

Fortunately, the interval immediately is changeable mid-shooting. Watch for it. If you need 7 or 9 seconds look for a display that says 5 and change it.

Was All of This Worth It?

For me, yes. It’s not even close.

That is the same answer Dan Zafra gave.

He put things this way, and I feel the same.

• 90 percent of the problems are user errors.
• The learning curve is steep but worth it.
• The app itself needs a lot of improvement.
• Support from Benro is weak.

I made plenty of errors, but the root cause was a Benro app interface that to put things mildly, is much worse than Zafra stated in his video.

Documentation is lacking. You are on your own, plus whatever help you can find.

Zafra has a great course. If you buy the Benro, take his course.

Hopefully I filled in the pieces on Canon and Nikon that he missed.

Is It For You?

• Zafra Yes: “I recommend the Polaris for any passionate photographer … willing to put in put in the time learning how to use the Benro, this is the tracker for you.”
• Zafra No: “If you want to have something easier, more plug and play, or don’t want to put in the time, I don’t recommend the Benro.”

To that, let me add another question: What’s your goal, and how committed to that goal are you?

Is your goal this?

That is Dan Zafra’s double-arch Milky Way in Death Valley.

It’s a 360 degree panorama of the summer Milky Way arch and the Winter Milky Way arch blended together.

I wish I could tell you that all you needed to get that shot was the Benro Polaris. Unfortunately, there is still more, lots more.

You need to learn PTGui, a software stitching program. And you need an astro-modified camera.

Astro Modified Camera

See those beautiful red colors above? For that, you need an astro-modified camera. On top of that, you need an expensive H-Alpha filter that has it’s own steep learning curve.

I spent a half hour on several occasions night trying to focus the Astronomik H-Alpha filter. Seriously, everything will look black, even at high ISOs on a very fast lens. If your lens is not F1.8 or better forget about it. Sony has a night view that makes things easier. Canon doesn’t.

Here is the trick I now use. I focus the H-Alpha filter in the daytime at infinity. This is easy for me because a tiny tip of Zion national park sticks above the horizon 35 miles away. If you can focus a 20mm F1.4 at 35 miles, you are at infinity. I then tape the focus ring and leave the camera turned on.

Spencer’s Camera is the place to go for Astro-Modified cameras. Tell Clarence I sent you. He does the astro modifications for NASA.

Get the H-Alpha mod, not the full spectrum mod. You can also get a filter that will convert the camera back to day time use.

I took this image with a Spencer-modified camera with his filter to convert to daylight.

Q: So can I use one camera and do everything?
A: Unfortunately, no.

Spencer’s filter does a beautiful job in most cases. But the flare on a modified camera is god awful when pointing at the sun.

Astronomik (the H-Alpha filter maker) makes a drop-in filter but the color correction is terrible and the flare is even worse.

My intention was to have a dual purpose camera. And you can get away with that until the sun is in the picture.

So, you need two cameras. But get Spencer’s filter not the Astronomik filter because that will give you a backup camera with the above sun limitation.

By the way, you will potentially need a Spencer’s filter for every lens if the lenses are of different diameters. Yikes! But almost all my canon lenses have the same filter size. My 100MM Macro and my main 20mm lens I use for astro have a smaller filter size.

The easy solution is to buy a step-up ring for the 20mm lens and the 100mm macro lens. I get by with a single 77 MM Spencer’s filter for all my lenses.

Extreme Possibilities

Please check out this image by Angel Fux.

That’s an amazing triple arch Milky Way shot in the Alps at 4,000 meter in the alps via a helicopter drop in hugely negative temperatures.

She describes the shot in her blog, The Night Above Everything

I draw the line here. That shot is beyond what I am ever going to try.

You don’t have to be that intense. And you don’t have to even get as extreme as double arches or use H-alpha filters. But you do need a strong level of passion or the Benro risks becoming a paperweight.

But if you are going to use the Benro, you need to learn how to stitch images, focus stack, do a multiple image astro stack, and do a technique called star reduction. All of these things have their own learning curve.

Zafra has an academy of courses.

Once you are using a tracker, ANY tracker, you need to learn how to blend images.

When you are tracking the stars, the land is blurry. If you are working with mountains, blending is somewhat easy. If you have trees in the image, then you need to get damn good at blending.

This is why some photographers don’t bother with any tracking at all.

And just basic stuff, tracking or not, requires techniques that capture star colors without blowing out the highlights. If you are just getting started, or having difficulty capturing the colors, I recommend Angel Fux’s Presets.

It’s a nice bundle, with presets for Canon, Nikon, and Sony, for both modified and unmodified cameras. Without a modified camera you cannot get an image like those above.

But that does not negate using a Benro. It just means you cannot get some of those exciting colors.

Even with Angel’s presets, I spent hours working with color adjustments to get the colors I wanted. Blues are very easy to blow out. I turned down blue and purple luminosity a lot. If you overdo that idea you get very ugly blue or purple fringing.

Add this to your learning curve. But here’s a tip. Spend as much time as it takes. If your blues and yellows are not blown out, you are off to a good start. Then get the background sky a nice neutral blue-gray or whatever to your own taste.

If you are still reading, you are either very passionate or you are interested in what may seem like torture.

I am simply trying to state that once you jump to any tracker, there is a steep curve, and the pickier you are about getting a great image, the steeper the curve.

Recommendation If You Buy a Benro

Practice at home in your house. Aling the setup and click on “Go to Polaris” (North Star). If the Benro points generally North and not negative, you are in good shape. But don’t click OK. Click continue. Practice moving the joysticks to move to a corner. Pick different points in your house an move there. Pretend they are the North Star and maneuver the Benro there.

Switch back an forth between shutter mode and USB mode. Take some double row panoramas in pro mode.

I forgot to mention more gotchas in pro mode. You need an overlap of 50 percent or in some cases, PTGui will not stitch the pano. The Benro default is 40 percent, another annoyance. For H-Alpha images, I strongly recommend a 60 percent overlap, and that’s now my default for everything.

The Benro does not remember your settings. It should. That’s another issue, just one you need to remember. It’s easy to forget the overlap because you have to scroll to see it, yes, yet another annoyance.

And if you set start and end points and take a pano, well maybe 40 percent will stitch and maybe you you set more control points manually in PTGui.

I took a row at 40 percent. Then changed it 50 percent. Well guess what. That change somehow screwed up the start and end points. It shouldn’t. Benro was wildly off when it started taking my pano series. Add that to the Benro bug list.

Autofocus Mode

Autofocus is another problem ready to bite you. Your camera need to be in manual focus. The app needs to agree. And in the app, it’s damn hard to tell whether you are in autofocus mode or not.

I accidentally must have turned on autofocus in the app. Expect totally black images if you do. Not always, it’s random.

What happens is Benro or the camera or both want an autofocus confirmation. If the camera and app don’t get that, it takes a picture for one second. It will be black. And that might not happen until the third frame.

If you are in your car waiting, you will not even know until you review them. I was there and noticed a fast image.

Waiting in the Car

If it’s cold or windy you may want to go to your car if it’s nearby.

If you do, remember to leave your phone on the ground by your tripod. The app needs that phone to communicate to the Benro and if you accidentally take your phone away, it all stops.

If you are leaving to go anywhere, put the phone on the ground.

Expect Problems

That’s the message here. Make the best of it. Zafra describe one situation where the Benro did not work.

I ran into that issue many times. The worst time was when I was trying for my own 360 degree double arch Milky Way. It’s only possible 3-5 days per year and if weather does not cooperate, not at all.

I described my attempt in my post How I Shot and Stitched a 360° Twilight Panorama at Kolob Canyons.

This is the land portion. Note the tree on the extreme right and left are the same. I am very fond of blue hour blends.

This image is well after sunset in the blue hour. The anticrepuscular rays are a big bonus.

When I went to take the night sequence, the Benro stopped working completely due to the connection problem I described above.

But what do you do?

The only thing you can do is try to make the best of it. I had no tracker. But I did have a fast lens. So, I manually too sequences using the setup I described in the above post.

Here’s half of the result which I never posted.

Conceptually it looks like the following work in progress, with lots of errors. Mentally blend the following with the land only image above.

There are a huge number of issues here. Perhaps I should be embarrassed to show this. But It’s useful for instruction.

Take lots of overlap. I did so at the ends, pointing North. Note the right and left image are the same. The 360 degree shot merges North.

I did not do star reduction here. It badly needs it. Nor are the colors the way I want. And I certainly don’t have the H-Alpha shot. These are manual images for 8 seconds on a 20mm F1.4 Canon lens. That’s an amazing lens.

For instructions on how I took the land portion, I repeat check out How I Shot and Stitched a 360° Twilight Panorama at Kolob Canyons.

The land panorama requires some effort in and of itself. Because I have near objects, a pano will not stitch properly without a nodal rail.

I describe nodal rails and how to use them in the link.

Was this a success? I think so. I like the land shot.

Anticrepuscular rays are the shadows of clouds or mountains cast away from the setting sun, appearing to converge on the antisolar point (the exact opposite direction from the sun in the sky).

There I was, with a tracker that did not work (but I did not know that yet).

So what do you do? You make the best of it. You take Milky Way shots and see what works.

Here’s one more tip. Get Dan Zafra’s Capture the Night filter.

Capture the Night is a premium astrophotography filter that creates a natural starglow without sacrificing background detail, cuts through light pollution to recover contrast in the night sky, and gives a subtle boost to Hydrogen Alpha nebulae. It is compatible with both standard and astro-modified cameras.

I did not have that filter when I took the above images. But I have used it since, and the boost is very good. I will review the filter in my next Milky Way post.

What was it like at Zion that night?

Bob Dylan explains.

Yes, to dance beneath the diamond sky
With one hand waving free
Silhouetted by the sea trees
Circled by the circus sands Milky Way
With all memory and fate
Driven deep beneath the waves
Let me forget about today until tomorrow

Yes, the Benro is worth it, for me.

You now have the pros and cons, for you, with all the details.

Mish.