DOF Questions

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djembeplay

Well-known member
Hey guys. I couldn't seem to find these particular questions anywhere in other posts so I figured I would run em' by you pros real quick... so sorry if they are redundant. Also, I don't have an HVX... yet.

First, I was just looking at the redrock M2 adapter and footage. I am wondering... just how much of an increase in DOF does it give you (as compared to the stock lens fully zoomed)? I do a lot of nature videography which means I like to keep things light... and this thing is a pretty large add-on. But, if it is a dramatic difference, I may consider it in the future...

Second, I have also been eying the A1.... While I think I will go for the hvx based on preference of features (and am a current dvx user)... I was wondering how the DOF is on the A1 lens compared to the HVX... More specifically, how would the DOF compare with the zoom equal (i.e. 13x and 13x) and also how would the DOF compare with the zooms full on each (i.e. 13x and 20x).

Thanks guys.

-T
 
1. That is going to depend on the lens you use with the m2 and how you use it.

2. After weighing up all cameras I would go for the HVX no matter what until Panasonic updates it.
 
Hey guys... Ya thats what I meant... how much of a decrease in DOF, not increase. I was tired :).

Well... how much of a decrease if you used, say, an 85mm?

As for terminology and figures, go easy... im new to understanding lens attachments.... which also leads me to this question... what is the purpose of a matte box? Is it solely to avoid lens flair?

Thanks-

Tejay
 
Also research the "Brevis35" (google CINEVATE). It's loses less light and screws onto the HVX lens - you don't have to use rails (though i guess you might with the long 35mm lenses you'd use).

Ian
 
Im not sure what is what actually.

Basically, I just want to know:

1. If the A1 lens has a shallower depth-of-field than the HVX when they are at equal zoom and f-stop. I also want to know if it is more shallow on the A1 when fully zoomed due to the 20x vs. 13x on HVX.

2. What exactly is a Brevis or a Redrock... They are holders for gels and filters? And that is different than a 35mm adaptor? And what I want to know most of all is... lets say, in terms of percentage, how much of a DOF decrease a 35mm adaptor would provide.

Thanks guys.

-Tejay
 
2. Brevis, redrock M2 are 35mm adaptors. This means you can put your nikon, canon (among other) lenses on them. You can get very shallow DOF with an adaptor. It might be beneficial to have an adaptor for you to get in close to distant objects. Your best to look up the cinevate or redrock websites and download some footage, there's lots of footage from adaptors on this site too.

An adaptor allows you complete control over DOF which the stock lens can't. I don't know if you will get an answer to your percentage of DOF question as it's kind of an apples an oranges thing.

An adaptor will cost US $1000 +.

A MATTE BOX is what holds the filters in.

Ian
 
djembeplay said:
Im not sure what is what actually.

Basically, I just want to know:

1. If the A1 lens has a shallower depth-of-field than the HVX when they are at equal zoom and f-stop. I also want to know if it is more shallow on the A1 when fully zoomed due to the 20x vs. 13x on HVX.
Click to expand...

When they are at equal zoom, the DOF is equal. When fully zoom in at 20x vs. the HVX's 13x, the A1 has a shallower DOF.

djembeplay said:
What exactly is a Brevis or a Redrock... They are holders for gels and filters? And that is different than a 35mm adaptor? And what I want to know most of all is... lets say, in terms of percentage, how much of a DOF decrease a 35mm adaptor would provide.
Click to expand...

The primary advantage that a 35mm adapter gives you is DOF at close range. With the stock lense, you have to have a decent distance between the subject and the background or you have to back away so you can zoom in. Sometimes this isn't possible. I don't believe there's a qualitative measurement for how out of focus something is. Keep in mind though that a 35mm adapter costs valuable time to set up (even the Brevis). If you're doing run and gun or live event the time you spend screwing it on and off can cause you to miss the money shot. It depends on your need.
 
Awesome, thanks for the feedback guys.

Its mentioned all over here, but its such a tough choice b/w A1 and HVX. I could use the zoom and slightly more shallow DOF... but I could also really use progressive 60p. Also, im freaked out about HDV... someone gave the example of it having nice greens on leaves, but if they blew in the wind the hdv compression might freak out... which wouldnt be much fun.

-T
 
Just a note - HDV is supposed to be more taxing on your computer than DVCproHD.
 
djembeplay said:
Also, im freaked out about HDV... someone gave the example of it having nice greens on leaves, but if they blew in the wind the hdv compression might freak out... which wouldnt be much fun.

-T
Click to expand...

The instability of HDV compression is completely exaggerated. If it looks that bad then it wouldn't have been adopted by three major corporations (Sony, Canon, JVC). For 99.5% of your use you won't be able to tell the difference, and the other .5% are extreme situations that you're never going to find yourself in (like blizzards). I can't remember who but someone did a comparison on the A1 where they threw the worst situations they possibly can to test the compression. And I believe the result was like ONE instance of the compression failing in 24F mode and none at all on 30F. That should say something.
 
also, keep in mind that with a 35mm adapter, your image is going to be flipped, and you will need a seperate monitor to operate your camera. so now, with a monitor, and a lense adapter, does it sound reasonable to carry it around the wilderness for your nature shooting??? probably not.

I would go with an HVX, because of the wide variety of formats and frame rates. You could shoot some really cool overcranked stuff of birds and things, that would look way cool. (just a thought)

but basically, what it boils down to is not how shallow your depth of feild is, but the content, and composition of your shots.

also, although P2 cards are more expensive than tape, they are much more durable
 
Cool- thanks guys.

Endless- ya thats what I was thinking too. I love the idea of overcranking with a high shutter speed. I was thinking... I own a DVX100b right now and find the DOF great when fully zoomed - and for my style shooting, I almost ALWAYS have the option of being fully zoomed.

While I do love a nice shallow DOF on close-ups and what-not, I agree about the content / composition being the more affluent factor to overall impression of course. But that is more of a 'once you have the camera' consideration. Right now, im in that stage of being extremely obsessive over little hardware details of picking a camera... the 'before you have the camera' considerations. I have alot of time to pick what tool will best fit my needs, so I like to study and study before I make a decision. Plus I live in upstate, NY... we hibernate inside largely in front of screens for most of the winter.

Once I get the camera, then I hardly ever research or 'keep up on' the tech / hardware end of things. At that point, I will be harvesting the fruit of my research my using my chosen tool to then dance in the 'content / composition' realm (transition from engineer back to artist).

I use AE for alot of matte editing and compositing too, so the 4:2:2 color space is actually pretty essential for me. Incidentally, HVX shoots 4:2:0 on 1080p mode, right? If so, what would yeild a cleaner color space, 4:2:2 720p or 4:2:0 1080p down-ressed to 720p? Hmmmm..

Btw, endless, right now I am jelous of where you live. I just moved a little under a year ago from Santa Cruz (well, just north of Watsonville actually). Too expensive for me, but it looks more appealing in the winter months...

thx-

T
 
yeah, i'm about an hour and 15 away from san francisco. and the weather's actually been kinda hot these past days.

i think that the hvx would be the way to go. it is a really versitle camera, with all the formats, and shoots to P2 as well as tape. its almost an "all-in-one" camera.

it might be a good idea to just rent each camera and do some tests yourself. its a small price to pay to make sure you buy the right camera.
 
Ya thats a good idea. I live outside of Ithaca, NY now though, so its tough to find anyplace relatively close that offers such a service. Of course, Cornell and Ithaca College are right here... I wonder if they would rent to 'non-students' or if they have the camera... hmm, something for me to research.

Oh ya you guys have southerly air blowing up your way right? A friend in Oregon just told me about that. We have the opposite- Canada air came down for a visit... its gets below 0 lately... crazy. Actually, I cant shoot outside when it gets this cold (because of tapes), which is a bummer.

Incidentally, I am working on this project right now and I need a short shot of a lone tree against blue sky so I can chroma key it. I cant do it here b/c of cold and no leaves on trees! Haha... I am going to see if anyone here will send me a clip for a little money...

-Tejay
 
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