Best focal length for aerial footage of mountains

[Luke Humphrey]

Shooting some footage in the North Cascades, WA on Wed with a Dragon/Tyler Nose Mount.
I wanted to get opinions on the best prime focal length for this type of footage?
Currently looking at a Canon 14mm f2.8 II and a Canon 24mm F1.4 II. Crop factor on the Dragon sensor is 1.3 I believe so looking at effective focal lengths of 18mm and 31mm.

Footage will include sunset shots low flying over ridges. Some model examples:
http://www.youtube.com/watch?v=w1OnAA5i8ec - Shots: Mainly the opening shot, also shots at 0:12, shot at 0:16, shot at 0:20 (basically close flying over ridges and between peaks).

 

[Chris McKechnie]

You may want to consider a 35 or even 50mm if you have them. Will just enable you to get closer to thungs if you need to maintain a high altitude for whatever reason. Youmay dvdn zee some slight vignetting on that 14mm if youre shooting full frame 6K. I tend to always overcrank aerial footage, which will smoothen things out quite a bit. Yea,you eat through footage more quickly, but nothing looks as amazing as 6K dragon slow month aerial footage.

You could also throw on a tilt-shift lens for a pretty amazing effect as well.

 

[Vance Colvig]

Don't think you will find any vignetting, as those lenses are both made for full frame still cameras, I believe. I would probably opt for the 14mm given the limited info you give in your post. Have no idea if you want to show speed or senic majesty. The need to overcrank is certainly minimized with a wide lens as far as vibration is concerned. You might want to shoot at 48fps or 64fps though and use every other frame in post. Unless the time of day is important, early morning is usually cooler, calmer and clearer as a very general rule. By doing so, better helicopter performance is available and the air is generally calmer and cleaner.

 

[Gavin Greenwalt]

I like 18-24mm for wide shots out windows. Not sure what it would be like on a nose cam.

As to shots at :16, :20 you'll need like a 100-200+ mm

 

[Marcos Montenegro]

I like the Sigma 18-35mm on an Epic where you want to capture the whole mountain range. Be prepared to zoom in for the details, especially with the pov of an aerial view. I used the 24-70 and the 70-200 more often than I thought I would on shots down in Patagonia.

 

[Walter R]

We've done aerials a few times with different aircraft and rigs. The last time was over the everglades with a Canon 24-70mm on a Tyler mini in a Jet Ranger and I really liked that focal range, since 24mm gave you that sense of perspective, etc. but the 70mm angled downward gave a much better sense of rushing over the landscape.

In this particular case, I think you have the challenge of stability vs. focal length with your particular equipment and the shots you note in the video link - especially with a nose mount that I don't think has any gyro or other significant stabilizing built in. Generally speaking the Tyler nose mount is used with wider angle lenses, but to try to get shots like the ones in your link you'll want to be more telephoto. As Gavin notes, some of those are pretty definitely on pretty long glass. I would expect the shots in the video were done with a Cineflex or Gyron, etc.

In terms of the North Cascades, I shot there 4 or 5 years ago from a R-44 (door off) over the North Cascades. It was with a Canon XF-300 that I kept full wide most of the time since the R44 is a bumpy little bird and I was hand held. The pilot had flown a lot of rescues and was very familiar with the terrain and the airspace so he was comfortable getting fairly close, but even so, on a wide lens when you're passing over and between peaks etc. they still look pretty distant on a wider lens. For our project we got what we needed (with significant post stabilization), but our shots don't really have the sense of proximity, etc. you see in the video you referenced. I think the equivalent of XF-300's lens wide is probably close to a 24mm on the Epic. So definitely not the 14mm, probably not the 24mm - again, at least not for the shots you appear to be after. I would probably use a 35mm, since I'd be dubious about going any longer with that particular mount. But I think you should talk to Tyler, your rental house or pilot and see if they think any input on what focal length you can get away with and you may want to consider a 50mm. You can always have the pilot fly a little higher (and probably get a smoother ride) if you are too telephoto, but you don't want to find your lens is too wide to get the shots you want.

You'll have the advantage of a larger, more stable aircraft (I sure hope!) and you can obviously over crank to help smooth things out as others have mentioned, but just remember that over cranking can make it feel a little more floaty/magestic, rather than giving you that sense of speed over the ground and past the peaks. I think 48 fps for a 24fps master is a good choice for post flexibliity or 60 for 30 if that is your time base. Either way, shooting with a higher shutter helps with post stabilizing. If you wind up with any high frequency shake you're taking out with stabilizing the motion blur from shooting 1/48 shutter can give focus jiggle once you remove the image jiggle.

As Vance says, go in the morning (sunrise instead of sunset) if it makes sense for the light you're after based on the orientation of any specific peaks, etc. Not only is there usually less wind in general, but the sun heating up the mountains can create a lot of localized turbulence due to the temperature differentials of the sun heating up exposed patches of stone adjacent to areas of shadow or snow.

One last thing that may be obvious or already in the plans, but a A DP we've worked with who shot a ton of car footage with the nose mount always emphasized that with the nose mount in particular you had to have a monitor for the pilot - but of course make sure they are okay with it and that it is placed where it doesn't interfere with their line of sight. With the nose mount and a fixed lens as long as your exposure and focus are okay, your pilot is your camera operator. Besides actually helping them get you better shots, if they can't see what the camera is seeing it will be much harder to explain any changes you need to get the shots you want.

These are just my thoughts about what I would do based on limited experience and what I think you're after. Please report back after your shoot and let us know how it went. Better yet, post some footage!

 

[Luke Humphrey]

Thanks all for the input - I appreciate it. We ended up going with a Canon 24mm cine lens. found out that the footage in my reference clip was def. telephoto, which was not going to work with the Tyler mount.
We did one 2.1 hour run and changing lenses or focal lengths was not going to be an option.
We shot at 48fps with at 1/96 at 10:1 and filled up a 512GB mag just as we finished.
High frequency vibration was def. a problem in many of the shots, it seems like it's primarily tied to the speed of the JetRanger (too fast = more vibration). Seeing what we can do in post to clean it up with Warp. Might try Mercalli as well.
If you have any tricks for getting rid of the vibration I'd love to hear it.
Will post info more later, but we definitely did get some beautiful shots that are keepers - especially closer to sunset.