GH2 Focus Plane Shift While Zooming makes the 14-140 useless

Turbodog, maybe that example you posted is just not a good one. The lens seems soft, and I understand this is at the lowest aperture value but my vintage Nikkors seem sharper than that even wide open.
Also, I'm noticing it gets even softer around the corners (like on the drummer).
The ability to power zoom a constant aperture lens is really cool, but I'm not sold on the look of it.
 
I think you're missing the point as to why cinematographers are so excited about using DSLRs. It's not because it's easy, or convenient, it's because shooting with a Canon 5D Mark II or GH2 is the next best thing to shooting with a $50,000 Red. It's a movie camera for the cinematographer on a budget. It's not meant to replace a camcorder. Last year's season finale of House was shot on a Canon 5D Mark II and George Lucas hired a DSLR specialist to use the 5Dmkii for B camera work in places where a normal cine camera won't go. Does this mean some extra effort to rig the camera properly? Yes, it does.

A lot of people are picking up vintage SLR lenses and using them with adapters on the GH2 with good results. An SD video lens that originally cost $5000 or more with the proper adapter can produce nice results, as shown in my footage and the footage in the link I provided where they compared an SD lens with the 2x extender with an HD lens with a $5500 optic adapter, and they concluded that any difference was impossible to see. With the GH2 and a proper adapter, the SD lenses are a great bang for the buck. If you have the budget for a RED or ARRI camera, then of course you will want to shell out the big bucks for a PL cine lens.

"My experience with 2x extenders is that they degrade the image and make it look low-contrast and milky." I can only relate to what I'm seeing on the GH2 and AF100, and that's not my experience. My footage was shot wide open with the 2x extender. Does it look low-contrast and milky to you? What about the footage at the link I provided?

"the GH2 crop mode is great, but that eliminates the shallow DOF advantage of the GH2, and makes the image more noisy by about 2 stops, yes?"
Yes, it does make the image more noisy by a little over 2 stops. But now you can use the lens in the 1x mode and gain back 2 stops of light, so it's a bit of a wash. The crop mode is equivalent to a 1/2" sensor. That's still better than the 1/3" sensor of many prosumer camcorders in terms of depth of field. And there is the benefit of using the "sweet spot" of a 2/3" ENG lens, the sharpest part, and cropping out those softer edges.

"(chromatic aberration) is a real issue. It's something I had to contend with everyday with broadcast lenses. Open up any wider than f4 and highlights looked cyan and magenta instead of white." I shot my footage wide open. Do you see where CA is a significant problem? I don't. Nor do I see any cyan or magenta in the hightights. I'm just not seeing it.


"I was referring to the Panasonic kit lens with its variable aperture, and to the tendency for 35mm still lenses (which are the most commonly used lenses for DSLR video shooting) to be softer when wide open."
The Panasonic lenses are corrected for CA and distortion in firmware so they certainly do have that advantage. But they are also slow, and of course a f/1.4 - f/2.8 DSLR lens is going to be softer wide open. When you are shooting people, sometimes a little softer is a good thing. My post was directed at the OP who found the 14-140 "useless" because of focus plane and iris shift while zooming. The B4 video lenses are both parfocal and fixed iris. Find me a micro 4/3 lens that is parfocal with a fixed & stepless iris.


"In order to get the same performance as a prosumer camera, you had to go DIY and make that (zoom power cable)" I had fun going DIY and making the power cable! And now I'm manufacturing them so that others don't have to go DIY. It's part of the creative process.

"probably need rods or some kind of lens support to properly balance the camera on a tripod.". No, take a look at the photo in my first post. The B4 to micro 4/3 adapter has a heavy-duty tripod mount built right onto it. A rail support is totally unnecessary. Of course, if you are a serious cinematographer, you may want some accessories like an LCD screen, lights, a backup battery, etc. I've got a rail support system for less than $150 than can do all that. That's the beauty of it, you can go as stripped down or as elaborate as your needs dictate.

"Can you go hand-held with that thing without using a rig?" Yes, for shorter takes you can go hand-held by just using the grip on the side of the lens the way it was originally intended. For longer takes and more stabilization, you can go with one of the many shoulder support systems available. You don't have to spend a lot. Opteka has one for $100. But again, it's not necessarily intended to replace a camorder. They each have their functions.

"the "cool-factor" of shallow depth-of-field can work against event videography because it's more difficult to keep an unpredictable subject in focus." Then perhaps most event videographers should just stick with a camcorder. This is a GH2 forum, the reasons people come here is to discover better ways to use their GH2, not to be told to get a camcorder.

"I meant heaving to constantly manually pull focus." If you're a cinematographer, manually pulling focus is standard procedure. They have marks for the talent and marks on the lens. It's all very controlled. Event videographers may or may not want to deal with manual focus. It's a personal preference. I didn't find it to be a problem on a tripod. I just zoomed all the way to grab focus, then zoomed out.

"I don't like the bokeh on broadcast lenses." If you want to pick apart a $500 - $1000 solution, you can always find faults with it. The bokeh on the Panasonic 14-140 is not particularly pleasing either.

"My GH2 set to 6400 ISO is not going to look less noisy than a prosumer 1/3" camcorder at 400 ISO." Actually my math was off, it's actually equivalent to ISO 3200. Not less noisy, the same. There is a lot of noise reduction going on with a small sensor camera, but as far as the RAW signal goes, a sensor that has 16x the area is going to have 8x the signal-to-noise ratio. That's just physics. From Wikipedia:

"the noise level produced by a Four Thirds sensor at ISO 800 is roughly equivalent to that produced by a full frame sensor (with roughly four times the area) at ISO 3200, and that produced by a 1/2.5" compact camera sensor (with roughly 1/16 the area) at ISO 100. This ability to produce acceptable images at higher sensitivities is a major factor driving the adoption of DSLR cameras, which tend to use larger sensors than compacts. An example shows a DSLR sensor at ISO 400 creating less noise than a point-and-shoot sensor at ISO 100"

http://en.wikipedia.org/wiki/Image_noise

So you see, a 1/3" sensor @ ISO 100 is equivalent to 4/3" sensor at ISO 800, (8x)
so 1/3" sensor @ ISO 400 is equivalent to 4/3 sensor @ ISO 3200.


"No, I was comparing a $500 SD "old broadcast lens" to the built-in lens of a $3,000 to $5,000 prosumer CCD camcorder." That's still 6 to 10 times the cost and how does that provide a solution to the OP or other GH2 users who come to this forum looking for answers?

"the hoops that you have to jump through in the name of shallow DOF are enormous." I don't know, I picked up up the B4 adapter and some lenses and stuck it on a tripod as was ready to rock. I don't feel like I jumped through any hoops. Do I want a modern micro 4/3 video lens for the GH2 and AF100 that has a constant aperture of f/2, stepless iris control, auto-focus, and parfocal zoom for under $1000? You bet your ass I do! But such a lens doesn't even exist, at ANY price.

So I'm turning to some creative solutions and having fun while doing it. Is the GH2 the right solution for everyone? Certainly not, I can understand where you're coming from on that.
 
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Turbodog,
Perhaps we're approaching this thing from two different directions. Maybe we're not even arguing about the same thing. I applaud your creativity and ability to make a DIY solution to mate B4 lenses on a GH2 and have powered zoom control. And no, I don't see any CA on your shots or on the shots in the example you provided. All I can say is that my experiments with B4 lenses show otherwise, and I know others have complained about softness and CA, also. So my guess is that sometimes you get a good deal and get a B4 lens that's really good. Good for you.
I own a GH2 (and a GH1) and love it. I am one of the most patriotic GH2 owners out there. And it IS cool that such a cinematic look can be had for such little money. I smile every time I think about little I paid for my GH2 and how great the footage looks. I own Canon FD glass, Nikon, Olympus and even a few Switar c-mount lenses.

But my original point is different than yours. I'm bringing up the more fundamental issue of what gets lost when you ditch a decent 1/3" prosumer camcorder in favor of a DSLR. Certainly, if you've worked with the AF100, then you must appreciate the XLR inputs, built-in ND filters, waveform monitor, etc. That's what I mean.
I'm not slamming the m4/3 format by any means. Though here's a hypothetical scenario that embodies my thoughts on the appropriateness of sensor size. If you had shot the close-up of the singer in your video using your B4 lens, you would have a HELL of a time keeping him in focus. Even if you were a great focus puller. Telephoto at f1.7 or f2 with an unpredictably moving subject? Good luck! I'm assuming that's why you used it for a wide shot and used your Vixia for the close-up.
Is cinematic shallow depth-of-field worth it if 50 percent of your footage is soft because of focusing errors? If the client thinks that's cool, then that's fine. But if they say, "why is the image going in and out of focus", then you have to wonder if there's a better tool for the job. It all depends on what your priorities are. That's what I meant.

Turbodog said:
So you see, a 1/3" sensor @ ISO 100 is equivalent to 4/3" sensor at ISO 800, (8x)
so 1/3" sensor @ ISO 400 is equivalent to 4/3 sensor @ ISO 3200.
Click to expand...

This is not a valid argument for several reasons. First, a 1/3" camcorder sensor has fewer pixels than a DSLR, allowing for those pixels to be larger and thus more light-gathering. Second, CCD is a different technology than CMOS. And third, there's 3 CCDs in a camcorder vs. one CMOS in a DSLR. The GH2 is a 16 megapixel CMOS sensor, so it's apples and oranges. Not to mention the variables of Noise Reduction, etc. All I know is that 3200 ISO on the GH2 is not going to look as clean as a good 3CCD camcorder at an assumed 400 ISO. I've compared the GH2 to a JVC HD250. I'm not a fan of the JVC, but I can confidently say it looks less noisy than a GH2 at 3200 ISO (assuming no NR tricks in post).
 
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dishan said:
Turbodog, maybe that example you posted is just not a good one. The lens seems soft, and I understand this is at the lowest aperture value but my vintage Nikkors seem sharper than that even wide open.
Also, I'm noticing it gets even softer around the corners (like on the drummer).
The ability to power zoom a constant aperture lens is really cool, but I'm not sold on the look of it.
Click to expand...

When zoomed in, the depth of field is only a couple inches. The drummer is well out of the focal plane and is supposed to be out of focus. And yes as I said when I posted it, the focus was a little off, it was slightly behind the singer's face. But still perfectly acceptable for a YouTube video.

It's asking a lot for a zoom lens of this range and vintage to compete with Nikkor prime lens. SLR lenses are going to be sharper in the corners, as they were designed to cover a full 35mm image size. With an SLR lens on a micro 4/3 body, you get the advantage of using only the "sweet spot" of the lens. But you will never find a vintage Nikkor zoom lens that has this incredible range, is this fast across the entire zoom range, along with being parfocal and having the ability to use servo zoom. This is just one (very versatile) tool to have in your bag.

Here is a better sample where I nailed the focus. You should view full screen at 1080 resolution, but you may have to wait for the high-res to kick in because I just uploaded it. I had to replay it before the full resolution kicked in for the whole clip.

The depth of field covers about from the microphone to the singer's ear. His shirt is in focus on the right side of the screen, out of focus on the left. His eyeglasses, beard and earring are good focus and are clear and sharp. His hand and the guitar headstock are in front of the focal plane. That's a thin depth of field. If you were outside or used additional lighting, you could stop down the lens and increase both the overall sharpness and depth of field.

This is in worst case conditions, a dark bar. I think it's doing well in these conditions, and does even better with good light. Yes, it's a "look". You may or may not like it. It think the whole setup and "look" is pretty cool though.


 
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dvbrother,

I just posted a clip where I got accurate focus on a tight telephoto close-up using the B4 lens.

I concede your points about CCD vs DSLR technology. And if I were starting an event videography company, I doubt if a GH2 or even (especially) the AF100 would be my first choice. Certainly the GH2 would make a great "B" Camera. But shooting video is only my secondary pursuit, so for me the GH2 is the right tool.

I do appreciate the XLR inputs, built-in ND filters, waveform monitor, etc. on the AF100 but I have been quite disappointed in it for several other reasons -- primarily for the fact that it does not even have the auto-gain and aperture priority mode that the GH2 has. I had thought that the move from GH2 to AF100 would be a natural move up, but I never dreamed that Panasonic would ELIMINATE features. Not having auto-gain puts a real limitation on the type of low-light shooting that I do. And I thought that I would be using the Panasonic lenses until I found out that none of them are "stepless" - the main complaint circulating on these forums about using them on the AF100 and GH2 is that not only do they jump light levels in obvious "steps" but they also make an audible CLICK when doing so. Professional videography it's not!

So to your original point about having to cluge old lenses to get things to work right -- yeah, people are finding out it's a pain... or, it can be fun, depending how you look at it! I'm enjoying the experimentation.

The one thing the AF100 has that's really nice is the "focus assist" function which REALLY helps out with these manual focus lenses and somewhat makes up for the loss of auto gain. I haven't had a chance to try out the AF100 in live shooting conditions yet or decided whether to even keep the AF100.


" If you had shot the close-up of the singer in your video using your B4 lens, you would have a HELL of a time keeping him in focus... I'm assuming that's why you used it for a wide shot and used your Vixia for the close-up."

Actually, it's the other way around. The Vixia is the static wide shots shot from stage right, (the left side of the stage to you and me in the audience). I was using the "low-light" mode on the Vixia and what it gave me was a 1/24 shutter speed, resulting in relatively low noise but that blurred motion video effect which is a "look" that is OK but not cinematic. The close-ups and zooms that you thought were from the Vixia were all with the B4 lens / GH2 from stage left. Even though I was slightly off it doesn't really go in and out of focus and also it looks much more like film to me. I didn't find the focus pulling to be that difficult (zoom in fully, grab focus, zoom out) but I was glad I had the unmanned Vixia "B" cam as another POV for when I was making adjustments, bumped the tripod, etc.

Optimally I would like to use more light and stop the lens down a bit to gain more leeway in depth of field and increase sharpness across the frame. The 1:1 crop mode is just another option that's nice to have. It crops out the softer far edges.

I'm also working on getting a Canon EF mount adapter made for these lenses which would then allow me to use a Canon teleconverter which is designed to cover a larger sensor, instead of the built-in extender.

For a few hundred bucks and some elbow grease, a talented person can make great images with these lenses without breaking the bank.
 
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GH2 not for documentary work

GH2 not for documentary work

I own a company that does corporate video but have started my first documentary that I am shooting myself with a combination of Sony 1/3 sensor camcorder and a GH1. Most of our corporate shoots at Memoriesfx http://memoriesfx.com/ are done using Sony EX1's but for the doc I decided to use the GH1 and quickly realized that it is a pain in the butt for anything that requires fast focus and quick exposure adjustment. So I am using it mainly for interviews where I can light properly and record sound into my Zoom H4N. I did one corporate video using mainly the GH1 http://vimeo.com/channels/memoriesfx#26917153 but it was much more labour intensive and frankly the job did not pay more.

The most important part of video or movie making is the story you are telling and if that sucks then it doesn't matter how good it looks because who cares.

The Sony EX1 and equivalent cameras do great jobs are best for run n gun docs unless you are really looking for a certain style that adds an element to enhance your story.

Having said that, the GH cameras do shoot beautiful video with the right conditions

Steve
 
For narrative projects where you can do multiple takes, tell the actors their marks, and control the lighting, the GH2 rules. Also, for just wandering around and catching b-roll, or shooting personal projects the GH2 rules. But when it comes to paid gigs where you have one chance to get the shot, the GH2 makes me nervous. I know many people are using DSLRs for this purpose and my hats off to them.
But yes, I love the fun in trying different kinds of lenses. I even shot a whole project using only 2 c-mount lenses and made the vignetting part of the look. I was hired to direct and shoot a project that looked like an old Charlie Chaplin silent film. I think c-mount lenses fit the bill perfectly:



Turbodog, question:
Did you shoot the B4 lens using the 2x extender or the GH2's ETC mode? You may have mentioned this already in a previous post but I couldn't find it. The reason I ask is that the DOF looks deep for f1.7 but perhaps that's because there's nothing in the background far enough away to go really soft. Also, do you remember what Film Mode you were using? Smooth? Cinema? Did you color correct this footage to match the Vixia? Curious.
 
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Turbodog said:
6. "The smaller chip gives you deeper DOF". Exactly. That's the VIDEO LOOK we're trying to AVOID. Cinematographers are after the FILM LOOK which means LESS depth of field. That is precisely why independent cinematographers are flocking to the large sensor GH2 and AF100.
Click to expand...
not exactly.
 
dvbrother I really enjoyed your short film. The casual observer might even be fooled into thinking it was the real thing.

To answer your questions, I shot the B4 lens using the 2x extender on the full sensor. That makes it effectively f/3.4 so twice the depth of field as f/1.7, but actually the same as f/1.7 would be on a 2/3" sensor. I can't remember for sure which film mode I was using but I know it wasn't Smooth. Most likely it was Cinema which is all I normally use but I have been trying Dynamic lately with the B4 lens to make it more punchy. I did color correct both the Vixia and GH2 footage: Both were a little too green and both overexposed and the spotlights made the highlights hot so I brought the brightness down quite a bit and the contrast down a little. The color correction was slightly different but they were pretty close to start with. I was afraid that the highlights in his face were going to be blown out but turned out to be not bad.

Sorry if I came off as defensive earlier; It's just that I'm rather proud of my Frankencamera. I agree with you about the lack of professional lenses for MFT and it has been frustrating to own these great cameras, the GH2 and especially the AF100, with no proper lenses suitable for live action shooting. I feel like Panasonic really let us down in that department, and the new two new motorized zooms they're coming out with are just more consumer level junk.

That's why I started getting into these B4 lenses, after reading this blog from editman:

http://theeditman.com/blogg/2011/08/24/NowThisIsFunCanonJ13x9B4OnTheAF101.aspx
 
Turbodog, it's cool.
It does look like the lens you have performs very well. I wish the B4 lens I used to have access to looked better, but it didn't have nearly the resolving power of any other lens I put on the GH1 (this was before I had my GH2).
FWIW, I recommend the Smooth setting for low-light stage venues like the video you posted. As you know, stage lighting can look cool in real life, but to a camera it's just horrid. Way too much contrast between the spotlight on the performer vs. the darker parts of the stage. Smooth is a lot less contrasty than Dynamic, so some of that detail in the shadows gets brought up. Smooth also handles highlights better IMO than Cinema, rolling them off in a more filmic way. Cinema tends to make highlights blow out in a funky yellow way (like the AF100), so the overexposure on your singer's forehead might look a little more pleasing using Smooth. That's been my experience at least. Have you ever shot a stage show that used LED lighting for everything and gotten a crazy horrid flicker across the whole image? With my GH2, I shot a comedy show that used these lights and no shutter speed could eradicate a pulsing flicker across the whole image.
 
Why this thread has gone on for so long is a mystery... well, other than opportunity for flamage... In the case of the 14-140 'kit' lens for the GH cameras... well sure... it is not going to be a $2000 or more lens... at kit price of under $1500... If one needs such... well... it costs more... buy the camera body, buy the adapter, if necessary, and buy a more precision lens as required...

The other bugaboo for me is rectilenearness... the 'video lenses' that I've seen on the fixed lens video cameras have sever distortion at the wide angle settings, to the point where they turn any one in to the fat/man/lady.

On the other hand for a couple of grand that problem is solved, if one can interchange lenses, and either the manufacturer offers such, or an adapter can be had to get such a lens on the camera.

As a note... for me... the 'zoom while filming' effect is way late 60's/70's... and should be confined to the history of filmmaking for the most part...

And of course... early on most people indicated the GH (and by extension many DSLRs) may not be 'competitive' with video cameras for 'event/news' reportage... duh... any more than a Speed Graphic Press is really viable for 'news reportage' in the modern world... despite the fact that a 4x5 negative is far superior to a teenyweeny 35mm...

CCD sensitivity is superior to CMOS, with effective ISO which can reach up to the high double digit K's or even triple digit K's... with appropriate sensor cooling... but that's not in the under $2K range, so it is not really a valid comparison.

Why I selected a GH-1 over 'whatever was in the video world', has more to do with being able to use my 'expensive' Nikon lenses, at a price I could pay for the camera... that is $2K and under... (The Canon was a competitor... but then I would have had to battle the Wife about getting Canon lenses...)
 
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