Realistic Alexa Mini Packages

What focal lengths are you typically using for flying? If you are flying wide angle (24mm and below) you don't really need a focus motor. You can also get away without focus motor most of the time with 50mm lens if you stop them down a bit (most daylight shots). Iris motor is a convenience but you can get away without it if you are careful when planning your shots. Plus it's a good idea to use lighter, photo lenses for EF mount.

While it always looks pro when you are flying with cine glass, Compact Primes are really almost the same internal design as Zeiss ZE photo lenses. Most of what cine glass has to offer is not really needed airborne. You don't need long focus throws because you won't be focusing most of the time (and if you will, the lens motors does it for you). You don't need the huge housing that's uniform across the entire line because you don't use a matte box and you still have to rebalance your camera on the Movi when changing lenses because each lens has a different weight and you need the perfect balance when airborne. You don't need these nice focus distance marks on both sides of the lens because there is no focus puller to read them. You don't care about focus breathing because, again, you won't be focusing.

The only situation where you need a focus motor is for some rare, artistic shots done with long lenses and wide open, where you want to play around with the depth of field. Focus breathing shouldn't be an issue here because it will be unnoticeable since you are flying.

By using light photo lenses and getting rid of the heavy PL mount in your camera and, altogether, you will save 500-700g in your setup.

Given the chance we would all like to fly with Master Primes or huge zooms but we need to settle on what's the most optimal way. While some fly full cine setup on ALTA with matte box, filters and focus and iris motors (or at least they post photos of doing so), according to Freefly's max payload recommendations they are all over the weight limit, especially on higher altitudes. If you are a good observer you will see that Freefly is no longer marketing ALTA as being able to lift full cine setups. In all their marketing materials nowadays they use Alexa Mini with light Leica R lenses, sometimes with Wedge and one motor. They are still using a heavy V-mount battery, but I guess they are doing it just because it looks better in marketing materials, compared to ugly LiPos strapped to the side of the camera.

Full cine setups are better to be flown with a bigger X8 machine. Here's hoping that Freefly will release something with higher lift capacity in the near future!

The M10 will be more than good with the Mini and cine glass, but you will absolutely need the full cage upgrade, otherwise you won't be able to balance the tilt axis at all. You should check the exact weight of the M10 after all upgrades (toad, toolless pan knuckle, full-cage) because it is possible that it won't be that much lighter than the M15. With the M10 you are throwing away half the fun because you can't top-mount it.

And here's a battery that's just a bit lighter for powering Alexa Mini: http://hobbyking.com/hobbyking/store/__56847__Multistar_High_Capacity_4S_4000mAh_Multi_Rotor_Lipo_Pack.html. Every single gram counts!

 

Michael, forgot to mention in the previous post that I am not flying ALTA, nor I have Alexa Mini for testing. We have a carbon fiber Dragon, though, so it's pretty similar when it comes to payload (although the CF Dragon is few hundred grams lighter than the Mini). I am currently flying a custom X8 setup, but it has lower payload capabilities than ALTA and uses the only possible FC option at the moment, that is A2, which has its own issues. I want to change it for something bigger to be able to fly the Dragon with confidence so I have been doing research, counting the weight of every possible setup and weighting pros and cons of either going for ALTA or a bigger X8. The price of both setups would be similar, but with the ALTA I would be able to finally dump DJI plus top mount the camera, which is a big plus. I am also closely monitoring all ALTA users to be sure that there are no issues with the machine. I have time till spring to decide so there's plenty of time for Freefly to perfect the machine and get rid of any issues that may arise.

So far, the conclusion is that you can't stay below Freefly's recommended weight limits with full Alexa Mini cine setup. In the previous post I just wanted to give you my insights as to why it's not really that big deal but you're right that some DPs are picky when it comes to gear. Sometimes they're right because they'll be using the gear in extreme conditions, and that's where things like lens choice matters most, but sometimes they just don't have enough experience with shooting aerials to know that 2kg $100k lens won't have any advantages over 400g $2k high quality stills lens. And the advantages for going with lighter lens are big when it comes to flight. All you need from lens in aerials is for them to be sharp, have good contrast and color rendition and be light, and you can get that all with Zeiss ZE/ZF or Leica (as well as many others). What matters most in aerial video for me is the camera choice, because only RED and Alexa have the dynamic range/resolution/fps needed to capture really great aerials with natural lighting.

That being said, it looks like most ALTA users don't care about the recommended weight limits and are happily flying heavier setups without any issues so far. Maybe they will chime in and offer their insights and experiences with flying ALTA with cine setups, or you could just ask them directly. For example Adam Varadi is flying ALTA with M15, Mini, bulky SDI->HDMI converter. Not sure what lenses he uses but they might be SuperSpeeds (pretty heavy lens). It also looks like he's running 2x10Ah packs.

 

Getting the Alexa Mini payload down to something within Freefly's recommended weight limits is all about compromise. We normally fly Alexa Mini packages on one of our Octo's (MTOW 19Kg) but this is fully loaded.

Powering the camera on LiPo's is essential if using an Alta, but so is limiting follow focus and lens choice.

 

I'm using the Alexa Mini on the ALTA, but even with just the necessary equipment the gross weight is around 15.6 kg. (Here we have a small mat-box for the filter but this was only to get the weight right, since we didn't have the Ultra Prime we will use, I had to add some weight)
By the way do you guys know what is the ver max takeoff weight fo the ALTA?

 

I flew around 20 flight with that weight, without any problem. All the motors were around 30C whille outside temp. was 15-20. So overheating s not a problem, very nice work form freefly!
Since the current was around 50-60 Amper / battery this shouldn't be a problem. ESCs are around 40C, so this is ok.
Flight time was around 10 min with 2x 10.000 TATTU (80 flights) packs.

I didn't use the ALTA on set until now, but next week I'm going to fly the Canon 1D C and RED Eoic for 2-2 days. Will let you know what happens.

ps.: i'm confident that the ALTA will fly everything that my Cinestar 8 did!

 

We need to fly 15 pounds regularly as well (Dragon and Mini with FIZ etc). Can anyone weigh in on how much thrust Alta required to hover at 15 pounds? Can Alta stay aloft at that payload if a motor or ESC fails? Our current X8 rig is roughly 40-45 pounds on average TAW with 15 of that M10 camera etc.

Thank you,

 

I know that the alta, with 2x 10A, Movi M10, Red Dragon, CP 2 lens, and 1 4200/4S battery was hovering around 70%.

i'm not sure if this video can provide any information, but I'm going to post it anyway.

 

Whats your voltage "loaded" before landing and then unloaded after landing?

 

Hy,

I'm draining the batteries to 21V worst case, mostly I land around 21.2. After landing the voltage gous up to 22.5V.

 

Noted, I was wondering how you where getting those flight times with the Alexa. 21v is dangerously low "3.5v per cell loaded" on a 25c battery. Gensace recommends not going below 3.6v cell loaded since the voltage can drop quickly after this (not have enough punch to support the amp/voltage draw).

 

In my experience (12 years modelling) the batteries hold the voltage pretty well down to 21V, (6S pack) that's when they start to drop.
Tested the ALTA with dangerously low voltage, I let it fly until 21V then left it hovering. The voltage from 21V to 18V dropped in 45-50 sec. This is why I land around 21,2V, this way I have around 2 min safety window. But this is just for me, I do not recommend this to anyone!
As you said the safest way to drain the batteries to 21,5V when loaded.

 

Quick follow up.
I flew the ALTA with RED and a small lens, the gross weight was 14.2 kg, outside temp. 15 celsius, and everything worked very well.
The copter was responsive, it held the altitude well, and flew for 12 min and landed at 21.3V (loaded), then charged the batteries with 7500 mah each.

An the best part is that the whole equipment fit in the trunk, wihout the need to fold down the seats. (only the 2 remotes were on the backseat)
This was the setup:

 

Having seen some bad crashes from hardware (ESC / motor / radio) failure, we absolutely can not fly Alta as 70% + hover leaves nothing to spare in case of failure. I find it astonishing that folks are willing to fly $100K+ rigs without enough spare power margin to recover in the event of failure even if insured for safety and economic reasons.

Thank you,

 

Hi Adam,

I am assuming that when you say 70% - you are referring to stick position on the Throttle?

Cheers

Andy

 

No, I'm refering to the motor % in the ALTA app.

 

Thanks Adam,

How has she been since your original post reply? It is a pain the lack of ability to lift within the higher regions. As with most on here, it seems to be the case that pushing 70% is too much risk? Then again, it is difficult to ascertain whether Freefly max lift figures have any 'flex' within them. Will be keen to hear how it is going for you mate.

Also - have any of you guys had further developments as well? Obviously I am late jumping in to the post! Similar situation here, however, the Alta is a phenomenal system and is flawless in flight. Currently flying a 5D until decision is made as to whether the Alta is going to be up to the job.

I think a trip Stateside is in order!

Cheers

 

Hy Andy,

70% is the limit for multi rotors, would push it any further. But as you saw I flew with a total weight of 15.6 kg and it was a bit wobly but didn't feel unsafe. But I don't recommend doing this.
Haven't flown with my ALTA since, it has crashed sadly and got the replacement yesterday. I'm selling this copter, because it's not suitable for the cameras/payload I'm using. (Bought a Hammer X8, that can lift 40 kg in total)

http://forum.freeflysystems.com/index.php?threads/alta-death-spiral-and-crash.7322/page-10

But have to say for small cameras it is the best copter out there!