Is it possible to pull focus on a lens while crash zooming?

[Josh Bass]

Right. And sometimes when you DONT do that you regret it later.

I worked on a short film a while ago that had some gun stuff. We didnt have a way to do the blood stuff or the gun stuff well but did it anyway...and I wish we’d found another approach...show a shadow on the wall when the gun flahses and someone is shot, cut to outside of the house wide and see window light up briefly (these were night scenes), ANYTHING besides what we did cause it looked meh and reminds you youre a)watching a movie and b) a zero budget one.

[Ryan Elder]

Okay thanks. I see what you mean. Well I can just use the gimbal to do the reveal then, or I can just cut ahead maybe.

I have a much bigger problem now though it turns out.

It seems that the lens will not focus at all if we turn the focus ring. Not just for zooms but for anything it won't. Is it because we have an adapter in between the lens and the camera, and we need electric power going to the lens for the focus ring to work?

But even if I use the Canon lens on a Canon camera, I am also having problems using the follow focus. If I make marks on the follow focus to focus from point A to point B during shooting for example, the lens does not seem to hit it's mark's as accurately. Is this because it's a fly-by-wire focus system, as oppose to mechanical?

If this is the case, should I just sell the lens and get a telephoto lens that is all mechanical so I don't have to worry about these electronic interferences and shortcomings? Plus it was said on here that it's easier to pull focus with a follow focus, on a mechanical lens, than a fly-by-wire one, so would trading this lens in for a mechanical just make things easier all around?

[Josh Bass]

Pulling focus is tough period unless your or your puller are very experienced at it. Solutions are stopping down the lens so people can move around more inside the available DOF and staging the blocking/conposin the shot to work within those limitations, or using wider lenses where you have way more in focus all the time, making it work stylistically. This is all from personal experience on zero budget stuff with dslrs and C100.

[Ryan Elder]

Okay thanks, but I watched this video on it, and they say in the video that pulling focus on fly-by-wire lenses, is much more difficult compared to mechanical focus rings:

Focus By Wire: Why It Sucks (Featuring Possible Solutions!) - YouTube

So even though pulling focus is difficult either way, isn't it still more difficult on a fly-by-wire from what they say?

[Josh Bass]

Probably? I have not tried one vs the other but the mechanical lenses are at least designed where when the ring is set at a certain place, youre focused (approximately) at a certain distance. It’s consistent and repeatable. Not so with fly by wire.

[Ryan Elder]

Yes, that is why I have been having focus problems with this fly-by-wire zoom lens, is that when I set focus marks, they don't seem to be the same each time and cannot be repeated, just as you say.

So I am wondering if I should just sell the lens and get a telephoto zoom lens that has an all mechanical ring, for around hopefully the same price, if it will focus better.

Or if you say to work with what I have, how does a focus puller suppose to set distances and marks with a fly-by-wire lens, or what do they do instead to compensate with the gear that they have to pull focus?

When I went to film school, they never even taught us on fly-by-wire lenses, and I haven't even heard of that until now on here. So what does a focus puller do to pull focus instead if they cannot set distances or marks?

[Pete Cofrancesco]

There isn’t any doubt that a cinema lens is what you need to pull focus. This is what everyone has been saying from the beginning.

It still isn’t easy and it introduces other issues. Mainly cost. You can buy cheap Chinese primes like Ronkino. Then you need a quality field monitor and focus pulling accessories.

Either you are doing this for a hobby or gaining experience to parlay into some commercial related video work that you can earn a living. You can only lose money making these type of low budget movies.

[Ryan Elder]

Actually I managed to find a hard stop telephoto lens on sale cheap!

Is the Sigma 150-500 camera lens worth buying, since it's on sale now?

It's the https://www.bhphotovideo.com/…/Sigma_737101_150_500mm_f_5_6…/BI/2855/KBID/3801 to be exact.

I'm usually uncomfortable buying second hand equipment cause it's been used and you don't know how worn out it is, compared to new stuff, or if there is any damage you find in the long run.

However the lens is on sale where I live for a hugely low price compared to a new Sigma model. So I was wondering if this lens is worth buying at all, even if it means needing an adapter to put it on a different camera possibly.

The person at the store said that since it's an older model it may not be as sharp and have some vignetting issues in the corners, but is he right, or was he just saying this so I would buy a new model perhaps?

I wanted a lens that can zoom into 300mm, for some long shots, where as this one zooms into 500 so a little more than what I need maybe, but for such a cheap price, is it worth the extra size and weight maybe to get a good 300mm quality lens, if it is?

As for needing a cinema lens, other people have been pulling focus on DSLR lenses though. On film riot, they even do this all the time. So isn't it possible since other people have made movie with DSLRs and DSLR lenses that have went on to win awards even? As for buying Ronkino lenses, I couldn't find a company called Ronkino. Do you mean Rokinon?

As for other equipment I work with videographers who have their own equipment and they help shoot as I direct. However, one thing they do not have is a telephoto lens, so I have to supply that for them, and just trying to find the best one for this project as well as future projects to invest in.

[Brian Drysdale]

With a stills zoom lens there is the chance that it will lose focus when you zoom in. Since this apparently varies from lens to lens the odds are that will do so until you test it..So it's best regarded a lens that has the option of various focal lengths.

Rokinon lenses are used by a number of film makers, although better when stopped down, they're not great when wide open. DSLR prime lenses are available that you can pull fucus on.

[Ryan Elder]

Okay thanks. Well I couldn't find any Rokinon lenses that go as high as 300mm since I want that for some other shots, other than this one I am talking about.

But I could still use a zoom lens for doing long pans and tilts, and for other shots, where I want high compression, where I don't require a zoom.

So let's say I say screw zooming, but still want a telephoto zoom lens with various focal lengths. I already have the Canon 75-300. But the problem is, is that I am having trouble focusing cause it's focus-by-wire.

So would it be worth selling and buying a Sigma 150-500mm, since that lens has all mechanical focusing, and would that make it easier, that it's worth trading in for?

[Pete Cofrancesco]

Yes Rokinon.

If you want to pull focus by wire be my guest.

A telephoto zoom is an odd choice of lens for cinema work.

[Ryan Elder]

Well there are lots of movies that use telephoto lenses though. Mainly the movie i am wanting to make has some running chase scenes in and the telephoto lens can track someone for a long time. The scene in The Good, The Bad, and The Ugly where Tuco is running through the graveyard, had a telephoto lens tracking him as he ran, so I wanted that kind of lens movement which you cannot get with a lens that is not telephoto. I also want shots with high compression, like OTS shots where the characters look real close to each other and a telephoto lens will get that high compression.

[Brian Drysdale]

Longer focal lengths are used in quite a few films, cinema has no focal length restrictions, Often the longer end of a 25 to 250mm zoom is used, plus there are also prime lenses. The Canon range has been a traditional favorite.

[Ryan Elder]

Oh okay thanks. When you say the Canon end has been a traditional favorite, why is that exactly? Anything I should be aware of there?

I also asked another filmmaker and he said that I should sell my lenses cause they are fly-by-wire, and that I should buy hard stop lenses instead. Do you think he's right though, and that fly-by-wire is that bad, that I should sell, and take the loss, and get all hard stops?

[Brian Drysdale]

The Canon lenses focus the "right" direction, unlike Nikon lenses. The lenses are modified with a universal mount, which meant that the lens mount can be quickly changed by the rental companies so that they could be fitted to a range of film cameras. The Canon 300mm f2.8 would be the main lens, but they had longer focal lens available in the Canon range.

The universal mount involves removing the rear of the lens and fitting a new section with a thread onto which the various camera mounts can be fitted. You can still buy these lenses, but they are professional still lenses, so aren't cheap and the modification isn't cheap either.

"Hard stop" focus allow you to to directly pull focus and use the markings on the lens, a focus ring that turns continuously can't be used this way.