ND Filters for X5?

[Richard Hurst]

I have just weighed the Heliopan 46mm 0.9 ND and that is 18g so thats too heavy also. I think standard photography lens filters will all be too heavy and we will have to wait for X5 specific made ones to hit the market

 

[Figbar]

I've been slammed with work...last I heard, these are a couple grams over the recommended weight, but like everything with this X5 system...whether or not these filters will be compatible is a big mystery. Not much help.

 

[larryzhou]

The X3 camera has a fixed aperture of f/2.8, and thus gives us only two controls for exposure: shutter speed and ISO sensitivity. That inflexibility all but demanded the use of ND filters to get appropriate shutter speeds (explanation below). The X5 camera gives us three controls for exposure: aperture, shutter speed, and ISO sensitivity. So in general, the X5 won't require ND filters as much as the X3. But they are still useful.

In video, the general goal is to use a shutter speed that is 1 over (2 x the frame rate). So if your frame rate is 30 frames/second, you want a shutter speed of 1/60 of a second. This video will

On the X3, we can't do it via the aperture (fixed at f/2.8), and we can't do it by lowering the ISO sensitivity (we are already at the mimimum of 100), so we have to do it with ND filters. Each "stop" on a filter effectively cuts the exposure in half. So a one-stop filter would allow us to change our shutter speed from 1/1000 to 1/500. A two-stop filter would allow us to lower it to 1/250, and a three-stop filter would allow us to lower it to 1/125. In this imaginary scenario, we would need a four-stop filter to get down to 1/60.

O.....

extremely helpful, thanks

 

[Bobby j]

So, I see Polar Pro has a 3 filter kit made just for the x5 for $99, available on 10/20, but no specifics about the actual weight of them. Anybody have anymore info about this? If standard lens filters are all too heavy, are options are pretty limited...thanks.

 

[Figbar]

The X3 camera has a fixed aperture of f/2.8, and thus gives us only two controls for exposure: shutter speed and ISO sensitivity. That inflexibility all but demanded the use of ND filters to get appropriate shutter speeds (explanation below). The X5 camera gives us three controls for exposure: aperture, shutter speed, and ISO sensitivity. So in general, the X5 won't require ND filters as much as the X3. But they are still useful.

In video, the general goal is to use a shutter speed that is 1 over (2 x the frame rate). So if your frame rate is 30 frames/second, you want a shutter speed of 1/60 of a second. This video will help explain why this is the case; the quick answer is "to get the correct amount of motion blur, so that the video looks good to the human eye and brain."

Another general goal is to use an ISO sensitivity as low as possible. The higher the ISO sensitivity, the more noise is introduced. I expect the lowest setting on the X5 camera to be ISO 100, which should give an excellent clean image.

So we start from there: ISO 100 at 1/60 of a second. And let's start with my favorite MFT lens, the Olympus M.ZUIKO 12mm, which has a maximum aperture of f/2.0. On a bright day at f/2.0 and ISO 100, a shutter speed of 1/60 is going to be extremely overexposed. Even at f/2.8, a proper exposure might require a shutter speed of 1/1000 of a second. The question: how do we get that 1/1000 shutter speed, which produces jerky motion, down to 1/60, which produces smooth motion?

On the X3, we can't do it via the aperture (fixed at f/2.8), and we can't do it by lowering the ISO sensitivity (we are already at the mimimum of 100), so we have to do it with ND filters. Each "stop" on a filter effectively cuts the exposure in half. So a one-stop filter would allow us to change our shutter speed from 1/1000 to 1/500. A two-stop filter would allow us to lower it to 1/250, and a three-stop filter would allow us to lower it to 1/125. In this imaginary scenario, we would need a four-stop filter to get down to 1/60.

On the X5, however, we have control over the aperture. So instead of adding a 4-stop ND filter, we could instead close the aperture by three stops. That would mean changing it from f/2.8 -> f/4.0 (1 stop) -> f/5.6 (2 stops) -> f/8.0) (3 stops) -> f/11.0 (4 stops). That would give us an equivalent exposure, and allow a 1/60 shutter speed. As an added benefit, closing down the aperture increases the depth of field, which allows more of the scene to be in focus.

So why would we ever need an ND filter? Note that the maximum aperture on the 12mm lens is f/22. That seems like a high number, but it is only one more stop than we are already using (f/11.0). If it's an extremely bright day, then we might need 6 stops of exposure to get to our target shutter speed, and the lens only provides 5.

Further, lenses tend to perform the best in the middle of their aperture (e.g., f/8.0 here), and worst at the edges (f/2.0 and f/22 here). I would expect to see less corner sharpness and more vignetting at these extreme apertures.

The great thing about the DJI app is that it gives us a live histogram during video shooting, so we can see what the exposure is. Learning to read a histogram, and to adjust your exposure to get a good one, is probably the most basic and important skill that the X5 camera requires.

I just re-read this post...makes a lot of sense. I'm seeing a lot of comparison demos that I think are ignoring all of this, posting bad looking X5 footage...I am also seeing some X5 footage that looks great. I appreciate your advice.

 

[Richard Hurst]

I just re-read this post...makes a lot of sense. I'm seeing a lot of comparison demos that I think are ignoring all of this, posting bad looking X5 footage...I am also seeing some X5 footage that looks great. I appreciate your advice.

I totally agree. We have people with new X5's that expect them to perform straight from the box like the fixed infinity X3. This is not the same, the X5 is a camera with varying apertures.Just just can't shove it on F2 etc and expect everything to be in focus. This is why we are seeing a lot of soft footage.

 

[InterMurph]

I wish we had an option to burn the camera settings onto the video. I would love to watch the aperture, shutter speed, and ISO setting change during a flight.

Or at least write that info to a separate XML file, which editing software could then use to achieve the same result.

 

[ajohnsonlaird]

I'm coming to this discussion late, but I have two questions:

1. If you stop down to a smaller aperture than f11 (depending on the lens you might get to f16), will that not cause diffraction effects to soften the image? Sure the DOF increases, and you can force a particular shutter speed to be selected, but does that not occur at the expense of reduced image sharpness? This effect is very noticeable on my Hassie H5D, but I've not done any experiments with, say, the Pannie GH4, nor the X5. There's a good tutorial on lens diffraction here.

2. If you really want to put a slightly heavier ND filter on the camera, why not add a small amount of adhesive lead tape to the back of the camera to balance it in the tilt axis? The X5 camera is statically balanced right out of the box -- with the lens cap on the camera nose dives, but without the lens cap, the camera stays in any position you put it. So with the small piece of lead you could bring the camera back into balance with the ND filter on. The overall net increase in weight is unlikely to overpower the stepper motor's ability to stabilize the camera -- at least I hope it would not as that implies that the motors are maxed out under normal conditions. (Adhesive lead tape is available sporting goods stores -- it's used for balancing golf clubs, tennis rackets, and cameras on gimbals such as the MōVI.)

Please bear in mind that I'm often wrong, but never uncertain....

Andy.

 

[InterMurph]

You are right; lenses are not at their sharpest either wide open or wide shut. This review shows that the Olympus M.Zuiko 12mm f/2 lens is sharpest at f/4.

And let's not forget that the MFT 2x crop factor affects not only the angle of view (12mm is equivalent to a 24mm lens on a full-frame camera), but also the depth of field. At f/2, an MFT lens will not give us the shallow depth of field that an f/2 lens gives in a full-frame camera; it is more comparable to an f/4 lens on a full-frame camera. So the depth of field at f/4 on these MFT lenses is more comparable to an f/8 depth of field seen on a full-frame camera.

 

[AutoAir]

I'm coming to this discussion late, but I have two questions:

1. If you stop down to a smaller aperture than f11 (depending on the lens you might get to f16), will that not cause diffraction effects to soften the image? Sure the DOF increases, and you can force a particular shutter speed to be selected, but does that not occur at the expense of reduced image sharpness? This effect is very noticeable on my Hassie H5D, but I've not done any experiments with, say, the Pannie GH4, nor the X5. There's a good tutorial on lens diffraction here.

2. If you really want to put a slightly heavier ND filter on the camera, why not add a small amount of adhesive lead tape to the back of the camera to balance it in the tilt axis? The X5 camera is statically balanced right out of the box -- with the lens cap on the camera nose dives, but without the lens cap, the camera stays in any position you put it. So with the small piece of lead you could bring the camera back into balance with the ND filter on. The overall net increase in weight is unlikely to overpower the stepper motor's ability to stabilize the camera -- at least I hope it would not as that implies that the motors are maxed out under normal conditions. (Adhesive lead tape is available sporting goods stores -- it's used for balancing golf clubs, tennis rackets, and cameras on gimbals such as the MōVI.)

Please bear in mind that I'm often wrong, but never uncertain....

Andy.

I'm sure an aperture above f11 will make for a softer image.

To point 2 though how will you know that you have achieved "balance" Some gimbal calibrations aren't neutral. They can be front or rear weighted based on the motor orientation without DJI's input on it we don't really know.

 

[Southerndude]

Why not just drop the f/stop down to f/32 or whatever is needed to get the shutter speed you want?
With the x5 you have a remotely controlled iris (aperture) which you didn't have with the X3.
You only really need ND filters for proper cameras when you want to get the DOF of a large aperture coupled with a low shutter speed.

You don't want to really use an Aperture above F11, (Varies from Lens to Lens), because using higher F-stops causes Diffraction in the digital sensor world. Diffraction causes Color Artifacts, and Blurring of the image. I would bet F8 is the real sweet spot for the 30mm Lens (35mm Equivalent) Especially since this lens is a wide angle lens. Now the Panasonic GH4-(Micro-Four-Thirds-Sensor) supposedly limits or reduces these Diffraction effects. I'm not sure, but I think the X5 Sensor is a Panasonic MFT sensor. The hard part with DJI, is they are so **** and limited on the release of specs.

They make pretty nice products and are fairly innovative to the consumer market, But, I hate there poor communications, and the Lack of information, and supportive mind set, It blows my mind! Someone is going to carve a whole in there market share some day, keying on there faults, unless they change. Sorry for the rant!

 

[Southerndude]

If you are from a video background then you surely understand aperture, shutter speed, and ISO and what they mean for your video.
When I shoot video with my Nex 7 I set the shutter speed to what I want and then measure what aperture I require to maintain that shutter speed for the available light. If I can't stop the lens down far enough or I want the small DOF from a large aperture then I apply a ND filter.
Circular polarizers are useful for removing reflections and generally make skies darker with more depth. They also have the effect of reducing the light level by a couple of stops too.

I would recommend not choosing any shutter speed that you want, You want to choose a shutter speed that is 2X the the (Frames-Per-Second), example: 30-fps = 1/60th SS, 24-fps = 1/50th SS
60-fps = 125th SS, it's called the Hollywood 180 degree rule. Reason why? It has to do with how the human eye perceives motion, Too fast of a shutter speed and the motion will look stuttering, too slow and it looks too blurred. Now the 180 rule is not cast in concrete. Some times higher and lower SS's can be used for effect by design. Filming landscapes where there is not a lot of motion in the shot other than the camera, you can get away with higher and lower SS's, I would recommend 1-Up or Down. Now if your filming a sporting event, car race, motorcycle race or where there is action, you want to stay pretty close to the 180 Rule, Again, unless you want the effects of higher and lower SS's. In the video world ISO is our exposure adjuster. because most of the time the aperture and the SS are fixed. Now in the X5 camera we do have the option to adjust the aperture. but then again, that has it's limitations, that's why ND filters and PF are popular for video.

 

[Figbar]

I'm coming to this discussion late, but I have two questions:

1. If you stop down to a smaller aperture than f11 (depending on the lens you might get to f16), will that not cause diffraction effects to soften the image? Sure the DOF increases, and you can force a particular shutter speed to be selected, but does that not occur at the expense of reduced image sharpness? This effect is very noticeable on my Hassie H5D, but I've not done any experiments with, say, the Pannie GH4, nor the X5. There's a good tutorial on lens diffraction here.

2. If you really want to put a slightly heavier ND filter on the camera, why not add a small amount of adhesive lead tape to the back of the camera to balance it in the tilt axis? The X5 camera is statically balanced right out of the box -- with the lens cap on the camera nose dives, but without the lens cap, the camera stays in any position you put it. So with the small piece of lead you could bring the camera back into balance with the ND filter on. The overall net increase in weight is unlikely to overpower the stepper motor's ability to stabilize the camera -- at least I hope it would not as that implies that the motors are maxed out under normal conditions. (Adhesive lead tape is available sporting goods stores -- it's used for balancing golf clubs, tennis rackets, and cameras on gimbals such as the MōVI.)

Please bear in mind that I'm often wrong, but never uncertain....

Andy.

DJI has allowed for us to use filters, correct? I don't want to even think about adding wei

I would recommend not choosing any shutter speed that you want, You want to choose a shutter speed that is 2X the the (Frames-Per-Second), example: 30-fps = 1/60th SS, 24-fps = 1/50th SS
60-fps = 125th SS, it's called the Hollywood 180 degree rule. Reason why? It has to do with how the human eye perceives motion, Too fast of a shutter speed and the motion will look stuttering, too slow and it looks too blurred. Now the 180 rule is not cast in concrete. Some times higher and lower SS's can be used for effect by design. Filming landscapes where there is not a lot of motion in the shot other than the camera, you can get away with higher and lower SS's, I would recommend 1-Up or Down. Now if your filming a sporting event, car race, motorcycle race or where there is action, you want to stay pretty close to the 180 Rule, Again, unless you want the effects of higher and lower SS's. In the video world ISO is our exposure adjuster. because most of the time the aperture and the SS are fixed. Now in the X5 camera we do have the option to adjust the aperture. but then again, that has it's limitations, that's why ND filters and PF are popular for video.

Which brings us back to the topic of this thread...filters. I'm thinking on a bright, sunny day, I will need to use a filter to maintain 1/60 shutter speed, apeture around f8 and iso at 100. Hopefully, the B&W filters that I purchased will be compatible. Again, thanks for all the information.

 

[johnmont250]

bw nd filters work great, no issues.

 

[Figbar]

Yippee! No excuses, now.

 

[ajohnsonlaird]

To point 2 though how will you know that you have achieved "balance" Some gimbal calibrations aren't neutral. They can be front or rear weighted based on the motor orientation without DJI's input on it we don't really know.

I'm making the inference that, with the gimbal dismounted from the I1, if I remove the lens cap and the camera is statically balanced in tilt and roll (it will stay in any position you put it in), then if you add the filter and a small amount of opposing weight to re-balance to that same condition, the motors will only perceive a slightly increased mass in motion.

Do you think this might be a false inference?

Andy.

 

[Quadpilot]

FYI, I have used both a B+W ND and CP filter on the DJI 15 mm lens and the Oly 12mm. No ill effects noted from adding the extra weight (ND filter is app 20 grams, CP 35grams).
I'm not claiming that the gimbal motors are not strained a bit with the weight compensation, but the video has been steady. Others have noted the same. YMMV

Just to be clear, I added no counter-balance weight to the gimbal.

 

[AutoAir]

I'm making the inference that, with the gimbal dismounted from the I1, if I remove the lens cap and the camera is statically balanced in tilt and roll (it will stay in any position you put it in), then if you add the filter and a small amount of opposing weight to re-balance to that same condition, the motors will only perceive a slightly increased mass in motion.

Do you think this might be a false inference?

Andy.

Not at all however most motors are more efficient moving one direction over the other. The calibration will take that in effect as well as mass and momentum which could be altered in a non static platform such as a drone.

 

[Gregg Smith]

This is a great point, however by changing aperture you change your depth of field. Granted some guys wont care about DOF, but if you are shooting high level production work, having full control over shutter speed and aperture is nice. This is where ND filters will come in handy. Also we have been using graduated filters a lot with the X5 and shooting scenes with a clear horizon line. They help out a ton with correctly exposing the sun and the ground. We have been playing around with a lot of 46mm filters on the market and they all weigh 20 grams+. The gimbal did not seem as fluid as with no filter. So we are going to produce some ultra-light filters for the X5.

Yes please!!!! I need a 6 filter set and a nice set of graduated filters. I have your ones for my X3 and for Phantom 3 Pro and love them. Hurry please!!

 

[Gregg Smith]

According to the X5 Manual they state the following:

Supported Filters:
Filters must have a weight of 7-11g, with those weighing 10-11g performing the best. Outside this range, the filter will decrease gimbal performance. DJI MFT 15mm f/1.7 ASPH supports filters with a size of 46mm.

As an FYI, I haven't installed any ND filters, waiting on the Polar Pro set to go live, but I tried to use the aperture, ISO and Shutter speed to control for good exposure, but running at F-16 and appropriate shutter at 100iso, the images were coming out soft and a bit out of focus. We messed around with it and some folks chimed in as well and came to the conclusion that this lens will most likely produce the best results for infinity focus at 5.6-8 and maybe as high as f-11. But if you shoot at f-16, like I did, it will not perform like you would expect from standard DSLR type camera.

One would think that f-16 would provide long DOF, but it doesn't with this camera. Please keep the thread going and post results from your X5's and share what settings are working best.

Thanks.