Reddit mentions of Fotga Slim 58mm fader ND Lens filter Neutral Density adjustable variable ND2 to ND8 ND16 ND32 ND400 for DSLR Mirrorless Cameras

Are you taking a film program in college? What sort of projects are you intending to use the camera for? Assuming that you're making a whole-hearted dive into filmmaking, here are my recommendations:

• SLR Magic 25mm - I've never used it, but it seems like a fantastic lens. The fast aperture combined with the BMPCC4K's low light capabilities will be an awesome combo. Great focal length too! That said, if you're willing to spend a bit more on glass, I'd look for something on the wider end as well. For me, 12-14mm is almost always sufficient. Sometimes I wish I had a 10mm for landscape stuff.
  
• BMPCC4K Bundle - It looks like a decent kit with a lot of basic essentials. You may be better off buying these things individually and investing in a better mic and tripod. It's important to have a fluid head too, which will allow you to perform smooth tilts and pans. The tripod included in this package just has a ball head so it's designed for fixed positions and may not deliver smooth movements. There are entry-level pro video tripods for $250-$300 on BH Photo. That said, a small tripod is a great tool to have. It lets you get the camera into places and angles that you simply can't with a bigger tripod. I'd recommend having both, but make sure your small one can get really low to the ground because that's the main limitation of a big tripod.
  
• Helios 44-2 58mm - This is an incredible lens. I'm sure you're aware, but it has a very significant character. It's creamy and smooth, low contrast and full of swirling bokeh. I love this lens, but I only use it when the approach calls for such a look. Its character is the entire reason it's so popular, but it may not match well with the 25mm you listed. Although I'm sure you could use that difference to your advantage in some ways. Just be aware that lenses have a great deal to do with what an image looks like in both obvious and subtle ways. There will likely be a noticeable difference in the bokeh, sharpness and contrast between these two lenses. Take this last bit with a grain of salt because I haven't actually used the SLR Magic 25mm. If you don't get the Helios, I'd recommend getting something else in either 35mm or 50mm.
  
• Samsung T5 1TB - Definitely a good idea. As far as I'm aware it's the best cost/space ratio for this camera. You may not need a 1TB though, so you could save some money here. I use this camera on small-medium scale commercial productions with a 500GB T5 and I haven't felt like I needed more. Record time depends greatly on what format and data rate settings you choose to record in. The most efficient BRAW setting (12:1) gives me just over 5 hours on the 500GB, while the highest quality setting (Q0 or 3:1) gives me just over 70 minutes. I generally use 8:1 of 5:1, but make no mistake, 12:1 still delivers incredible image quality beyond nearly anything within a couple grand of this price point. One thing to be aware of is that you can't delete files on the camera. This means you have to be very intentional if you want to get the most out of your recording space.
  
• Fotodiox Pro Adapter M42 to EF - Don't purchase this. The BMPCC4K has a Micro Four Thirds mount, this is for Canon's EF mount. This will be of no use to you.
  
• K&F Concept M42 to M4/3 - This is the adapter you need for the Helios 44-2.
  
• Lanparte Cage - The Smallrig cage is great and you'll save yourself some money too!
  
• Smallrig Universal Side Handle - A top handle is more valuable than a side handle. It allows you to do low handheld and one-handed operation much more comfortably. The camera body itself is designed to be held at its sides. If you have a bunch of cables connected to the camera and can't hold it on the left side, a top handle covers that too in most situations. I've got this one. It's awesome because you can slide the handle back and forth to balance the camera. A balanced camera makes a big difference.
  
• Juicebox Battery - Not a bad choice if you're on a tight budget. Looks like better Wh/cost ratio than lots of V-mounts. That said, I invested in v-mounts when I purchased this camera and I'm very happy I did. I spent a lot of time trying to find a cheaper alternative that would still be efficient to use in a working environment, but nothing seemed to be worth it for my needs. If you watch for sales on the budget brands (dracast, watson, etc) you can get them for pretty cheap. You'll also need a v-mount plate and a D-tap to 2-pin connector. As soon as you add a V-mount, you need a sturdy way to mount it to the camera. This means you're looking at a 15mm rail system. All said and done this could easily cost you over $500. The in-camera batteries last 45 minutes and you can get decent budget ones on Amazon. If you need to run the camera for 10 hours a day or more, go with v-mount. If you're just playing around for a couple hours a day, stick with your Juicebox or the internal batteries.
  
• Feelworld FW279 - Good budget choice. There are Feelworld models for half the price that will do the job if you want to save some cash.
  
• YXIAN DC to BMPCC4K - This looks like the right cable for your Juicebox.
  
  Things you're missing:
  
  
• HDMI Cable - Connect camera to monitor.
  
• SSD mount - Mount SSD to cage.
  
• Mini ball head or magic arm - Mount/position monitor on camera.
  
• ND filter - If you don't know what this is, it blocks light from entering the lens so that you can have more control over your aperture and shutter speed during bright shooting situations. It's like sunglasses for your camera. It will allow you to shoot at fast apertures to achieve shallow depth of field while shooting in broad daylight while maintaining a proper exposure. You can get variable ones which allow you to adjust the amount of light being block by rotating the filter, or a set of fixed filters that only block a specific amount. The variable kind typically has a larger trade-off in image quality, but are much more convenient and are cheaper than a whole set of quality fixed filters. I would recommend a variable ND to start. Make sure the filter thread size matches the largest of your two lenses, then you'll also need the correct step-up ring to use this on the lens with the smaller filter thread size.
  
• Computer - Dealing with this footage efficiently requires some decent processing power. What kind of computer are you running? If it doesn't have decent specs you may be looking at an upgrade.
  
• Storage space - This camera eats up a lot of space and if you're doing things properly you'll need backup drives. Your needs here will depend a lot on how much you're shooting and what kind of projects you're working on. I have an 8TB (4x2TB) RAID in my Mac Pro and backup to 2x 8TB drives. When my RAID fills up I make a copy to an archival drive, wipe the RAID and one of the 8's, swap another 8 in and start over. Hard drives fail, always keep two copies.

If the 12-35 is your primary lens, it would probably be easiest to just get a [$14.35 Fotga 58mm Variable Fader ND] (http://www.amazon.com/Fotga-fader-filter-adjustable-variable/dp/B00C2M94M4/ref=as_li_ss_tl?ie=UTF8&linkCode=ll1&tag=battleforthew-20).

If you plan to get larger diameter lenses later, you can buy the [$16.95 UltraPro 77mm filter] (http://www.amazon.com/UltraPro-77mm-Variable-Fader-Filter/dp/B007HOST8C/ref=as_li_ss_tl?ie=UTF8&linkCode=ll1&tag=battleforthew-20) I linked to above plus a [$4.99 58mm to 77mm step up ring] (http://www.amazon.com/Goja-Accessory-MagicFiber-Microfiber-Cleaning/dp/B0083WYARG/ref=as_li_ss_tl?ie=UTF8&linkCode=ll1&tag=battleforthew-20).

Hope this is what you're looking for!