ND Filters for X5?

[dronie]

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.

Would the reduced corner sharpness and vignetting apply to video as much as still photos?

 

[InterMurph]

It depends on how much of the sensor is used for video.

The GH4 has an MFT sensor with 16.0 megapixels for stills, like the X5. For photos, it uses the full resolution of 4608 x 3456.

When recording 1080p video, the GH4 uses pretty much the entire sensor, which means that it uses pretty much the entire lens, which means it is susceptible to edge softness and vignetting.

But when recording 4K video, it doesn't use the entire sensor; there is a portion around the edge that is not included. That is the portion where most softness and vignetting occurs. Thus, in 4K mode, it would suffer less than in 1080p mode, with the same lens.

 

[Rainbowers]

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.

CPL is dependent of the direction against the sun ! When you do a pan, it is not natural, changing from dark blue to light blue sky, only useful for straight line video shooting or photography

 

[PolarPro]

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.

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.

 

[Rainbowers]

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.

We think to produce too, as we are the specialists of ultra light !

 

[johnmont250]

oooooo snap, competition. its on!.............lol



but seriously. if the x5 can handle the weight, no one will procuce anything close to b+w filters.

(mic drop, and exit)

 

[Rainbowers]

oooooo snap, competition. its on!.............lol



but seriously. if the x5 can handle the weight, no one will procuce anything close to b+w filters.

(mic drop, and exit)

We already produced very high level ND for Hasselblad, we just want the weight exclusively light, as we did for the I1 with plenty of flexibility. But that is said already too much. BTW I have plenty of MPTV IR filters of Schneider, the best, except for one lens I found another producer with equal quality but more special design. I gave the factory 48 hours to think about the production for 46 mm. and no vignet at 17mm. I already use this filter on a 16mm full frame and I have nothing, Also on a 28-135 mm with nice bokeh. I am confident they can do, just price issue, they are not cheap.
And no competition for us, produce or not, makes no difference as it is not our bread. Only for pleasure, challenge, personal interest (as I consider to buy the I-pro too) and help the community as good as possible.

 

[Figbar]

oooooo snap, competition. its on!.............lol



but seriously. if the x5 can handle the weight, no one will procuce anything close to b+w filters.

(mic drop, and exit)

I just purchased 3 B&W filters, per recommendation on this forum. Am I OK with these? Do they weigh too much?

 

[AutoAir]

I just purchased 3 B&W filters, per recommendation on this forum. Am I OK with these? Do they weigh too much?

Overall I'm sure not. However if DJI's gimbal calibration doesn't account for almost an ounce more weight on one end of the system it may affect stabilization.

 

[InterMurph]

The B&W filters are definitely heavier than the SRP filters I bought for my X3.

But we won't really know until we get the X5 in hand. I remember hearing somebody from DJI saying that part of their lens-balancing strategy was to add a weighted hood to some lenses, so maybe these filters will actually be a benefit on some lenses.

 

[Rainbowers]

The B&W filters are definitely heavier than the SRP filters I bought for my X3.

But we won't really know until we get the X5 in hand. I remember hearing somebody from DJI saying that part of their lens-balancing strategy was to add a weighted hood to some lenses, so maybe these filters will actually be a benefit on some lenses.

... and the SRP's are much too heavy, 6 grams more on the top of the camera would need a counterbalance of minimum 15 to 20 grams. Warming up the gimbal motors is not a good idea. It is obvious that a well balanced camera is that much better.
I use zinc, environment friendly and not magnetic for counterbalancing.

 

[InterMurph]

So we are going to produce some ultra-light filters for the X5.

That depends on what you mean by "ultra-light". From page 7 of the X5 user's manual:

Supported Filters
Filters must have a weight of 7-11 g, with those weighing 10-11 g 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

The Balancing Ring must be installed on the camera lens when a filter is not used

 

[Figbar]

That depends on what you mean by "ultra-light". From page 7 of the X5 user's manual:

X5 User manual? I purchased 3 B&W filters...per recommendations on this forum...would love to know if they will work or if I need to return them...and then figure out what brand filters I should buy....any of this info in the X5 user manual? Up to this point, I have seen nothing on the X5 user manual, but I have been out of touch for a few days. Thanks

 

[InterMurph]

I can't determine the weight of these B+W filters. The B&H web site, which is usually full of such info, doesn't mention it.

 

[Figbar]

I just purchased...should be able to look at them when I get in my office...traveling now...maybe I'll try to call them and see if they think these are compatible with the X5.

 

[creativedogmedia]

I picked up the B+W XS-Pro Clear and it weighs 14g.

 

[Figbar]

According to the manual...which I just discovered on DJI website along with some raw clips....filters should weigh 7-11g...they say 10 - 11g is optimal....anything beyond this will affect gimbal performance...so I guess these B&W filters might not be the way to go? I purchased a polarizing filter and a 3 and 6 stop ND filters from B&H....I'm sure I can return these, but have no idea what filters I should purchase.

 

[creativedogmedia]

I am open to hear from some others who have found ones in the 10-11g range...personally, I don't think 3g is a big deal BUT if there are high quality options out there I will return this one and go for it.

 

[Figbar]

What he said...

 

[Richard Hurst]

Anymore news on this and the weight of the B+W filters?