1/4 inch sensors a good choice

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    • #48233
      AvatarEarlC
      Member

      Do cameras with 1/4-inch sensors have a place in professional video production? That seems like a really, really small element to me. I would think 1/3″ the minimum, and 1/2″ would IMHO always be the preferred size, and THREE of them, price being no object.

      I know that costs, to manufacturer AND consumer, are relevant, as well as the CMOS and CCD arguments that come into play, but really, 1/4″ … is THAT a valid option to someone who wants to go pro?

      Take the AG-AC7 currently being touted on the banner ads here, lately.

      What say you experts?

    • #198250
      AvatarRob
      Participant

      I know someone with a JVC HM100. It’s watchable as long as you know how to work a camera, provide enough light, and record clean audio. Since that’s what professionals do, then I’d say, “Yes,” to your question. Knowing the camera’s limitations are key as well. I wouldn’t shoot green screen with the HM100.

    • #198251
      AvatarCharles
      Participant

      Earl, I guess it all depends on what you plan to use the footage for. I think a 1/3 would be the minimum for theaters but I am sure 1/4 is fine for YouTube and such. Of course, it really helps if you know the capabilities of yourself and camera.

    • #198252
      AvatarD0n
      Participant

      the go-pro takes fine video…in good light…

      I think it boils down to how you use it, but yes small sensors CAN deliver the goods… but are they versatile? right now, in low light…no.

    • #198253

      Well, depends on what you want to do with the filming. I have been a 35mm stills serious amateur photographer for 25 years. I lived on Aperture priority because the eyes can be led, by selecting depth of field carefully, to what you want to focus on – it is one of the best tools in photography.

      When I bought my Sony Z5 with the 1/3″ sensors, I found out that I did not have that shallow depth of field tool and therefore, every damn thing was in focus (for all intents and purposes) and I could NOT select my target for the viewers eyes. Frustrated, I soon learned that the image sensor has a direct optical relationship to the quality of the boketh, that beautiful out of focus background that makes film so beautiful. I solved that with the Canon 5DMk2 where the film sensor is enormous – almost 4x the size of a Hollywood film frame.

      Now I have too much shallow depth of field and it is very hard to get a moving object in focus unless I stop down to f4-5.6 or a wide angle lens. Focus pulling is really a talent that needs a lot of care and practice, but the effect can be wonderful.

      So, what is the best? 4/3″, Canon 7D size, Red One sized sensors, the Canon5D if you stop the lens down to f4-5.6 or so, Sony NEX cameras. But the Canon does what Hollywood cannot do – super shallow DoF. It can be stunning if used right.

      1/4″. It will always look TVish, amateur non professional and if that is your game – go for it, but you will never get beautiful, emotional, warm and dramatic footage with wonderful boketh and selective DoF. The advantage is that you almost never have to concern yourself about focus. Not for me.

    • #198254
      AvatarJaimie
      Participant

      I think there is a lot of confusion about images sensors, depth of field (DoF), bokeh, low light performance, noise etc.

      First off, the image sensor is just that, it encodes whatever is projected upon it into three electrical signals that eventually become RGB or some variation of color representation. If two sensors have the same number of light sensitive elements, the larger sensor will be more sensitive to light (i.e. better low light performance) because the individual elements are bigger. In light sensing semiconductors, bigger is better because the larger elements gather more photons which raises the signal to noise ratio where the signal is photon-generated current and the noise is thermally generated in the circuitry (seen as “grain”). So much for the physics.

      Three sensors produce a much better picture than a single sensor for two reasons. The first is that they usually represent more and/or bigger light sensitive elements. The second is that the use of three sensors allows for better color separation filters. The down side of three sensors is the complex and expensive optical path.

      So, the sensor is responsible for low light performance. Given the same number of light sensing elements, bigger sensors are better because the light sensing elements are bigger. Picture quality is better with three sensors because of better separation filtering (don’t get excited, I’m summarizing, I know there are other considerations). Notice there is no mention of DoF or bokeh.

      DoF and bokeh are related to the lens and the sensor size or number has nothing to do with them. How can that be?

      Depth of field is related to lens focal length and aperture. If you want less DoF, use a longer focal length lens or a wider aperture or both. The reason that some persons believe that a smaller sensor causes greater DoF is that, for a given image size, the smaller sensor requires a shorter focal length lens. Think of it as a wider angle lens is needed to “squeeze” the image onto the smaller sensor. Since for any given aperture, the shorter the focal length of the lens the greater its DoF, it appears that the smaller sensor has caused the greater DoF.

      One way to decrease the DoF is to zoom to maximum telephoto and maximum aperture, setting shutter speed, gain and ND filters appropriately. Of course, the camera has to move back from the subject.

      Bokeh is an elusive quality associated with the internal construction of the lens. It is the way the out-of-focus parts of the picture appear as modified by the shape of the iris. In the still world, some portrait lenses are cherished for their bokeh alone. Sensors have nothing to do with bokeh. they can produce sort of a flare when overloaded that some people seem to think is related to bokeh.

      Finally, Bigger sensors are better because of their light gathering ability. A 1/3″ sensor has about 174% the area of a 1/4″ sensor. Three sensors are better than one because of more accurate color separation. DoF and bokeh are qualities related to the lens.

      To really control everything, you need a camera with a large sensor and a selection of interchangeable lenses. But, then again, that’s what Panavision is for. Jaimie

    • #198255
      Avatarvid-e-o-man
      Participant

      Jaime, thanks for the detailed explanation. Some of this I knew and some not but your explanation has lit some light bulbs for me. I am going to do a little more research into bokeh since I didn’t now anything about it before and your discussion has made me think that I should. Thanks again for taking the time to explain these concepts to us who need some enlightenment.

    • #198256
      AvatarJaimie
      Participant

      You’re welcome, I’m glad I could help. I think this business of bokeh, DoF sensor size is one of the most misunderstood in our business. It is not limited to video, the same discussions take place in the still photo world, too.

      There wasn’t much of this discussion when film was the “sensor” because the camera you bought dictated the film size and the lenses. If you had a 2 1/4 x 2 1/4″ Hasselblad you bought lenses that were generally accepted as wide angle, telephoto, fisheye etc. Most people didn’t pay much attention to the fact that their wide angle Hass lens actually had a longer focal length than the wide angle lens on their 35mm system but a shorter focal length than what was considered wide angle on a 4×5″ camera. Probably because the lenses were not interchangeable.

      Now, with digital technology, sensor size has become a camera selling point as an indicator of picture quality without any discussion as to how the whole system of sensor, lens, separation filters, gain, processors affects the final results. As you can see, it’s not complicated, just not well explained.

    • #198257

      Jamie: Well done, well explained. I am a boketh junkie from my still years, using Zeiss glass to achieve an incredible quality that melts ice. Each and every shot was composed and then a carefully selected aperture selected to get that precise effect on film and my shots won awards. It had a magical air about it. Most shots were wide open aperture which forced the eyes to see the subject and put distracting stuff in the back or foreground out of focus. It was simplicity.

      Now filming comes along. This is much harder to do as action takes place, the eye is not set on a single picture element, but on a story – so much more has to be said while following the action. The depth of field is more critical now, as the still work says one thing, filming says much more. Then you have to follow focus on the subject, or the reactions or whatever the film maker desires the audience to see, even if the speaker is not to be in focus. In other words it is controlling the emotions of the audience by forcing them to see what you want them to see and how much of it.

      Small sensors do not give that latitude by any stretch – not even close. Everything is in decent focus and that is a pain when I specifically do NOT want or CAN’T all to be in focus. It kills the story. And then you want to also have a beautiful boketh as well for the right scene.

      Not all bokeths are nice. I have a Zeiss 85 f 1.4 that up to f4, the iris diaphram blades do not form a clean even octogon circle, but the ends of the blades cause 8 detents in circle. When filming late at night with street lights (for example) in the background, you see these 8 sided, detented light shaped objects and it turns an otherwise gorgeous scene into a complete waste. But the softness in daylight is legendary. Some bokeths do not leave a softness, but multiple soft images as if in double vision. That is no good. And some lenses like my 180 f2.8 Zeiss leave an image to die for – incredibile boketh, control, contrast, color – like a diamond.

      So, selecting lenses is an art and must be carefully made and shot under all conditions. If you want cinematic qualities, shallow depth of field abilities, lovely boketh, as Jamie says, it is a big sensor on an excellent camera and the best lens you can afford. 1/4″-2/3″ will not cut it no matter how good the glass is.

    • #198258
      AvatarR
      Participant

      i have an hmc70 3×1/4″CCD and a JVC 3D camcorder 2×1/4″.

      i noticed that the JVC produces better in low light because it’s f/1.2 whereas the hmc70 is f/1.4.

      is sensor age a factor too? the hmc70 was built years ago while the JVC was just released this year. although 1/4″ newer, can newer mean better? cuz i read that the GH2 smaller sensor can perform just as good as the 5D full frame sensor.

    • #198259
      AvatarR
      Participant

      oh and the JVC 3D camcorder is a Backlit 1/4″ sensor which i notice to perform better in low light than my HF20 1/4″ sensor. perhaps being Backlit makes a difference as well. newer models are only 1/3″ backlit single sensors that are sold as prosumer.

    • #198260
      AvatarAnonymous
      Inactive

      Wow. Jaime! Thank you for providing the content I need to resolve this debate with a number of acquaintances who have migrated from camcorders to HDSLRs because the “…large sensor size gives them a short depth of field.” I was a trained photographer before I became a working videographer and tried to explain to them that while the sensors on HDSLRs are (generally) better in low light, more contrasty and more saturate, they had nothing to do with depth of field…depth of field is a function of the combination of aperture and focal length.

      I’ve complained for years that lenses on camcorders are too short and small.

      Short focal lengths and small aperatures, which throws everything in focus.

      I do what you do, especially for those pesky interviews: shoot at telephoto with the largest aperture you can achieve and as far away from the subject as possible, then put the subject as far away from the background as possible.

      I’m going to cut and paste your first post into an email and send it to some of my friends.

      Thanks!

      Toby

    • #198261
      AvatarAnonymous
      Inactive

      Oh…I guess I should mention that I shoot with 70% of my work with a Panasonic AG-HMC40 (2) and the remaining 30% with Sony NEX-VG10 (2)

      When I decided to begin experimenting with HDSLR, it made more sense to me to buy a dedicated camcorder than to go through the expense of making a HDSLR behave like a camcorder.

      When I need contrast, saturation, and short DoF, I go with the Sony. When I need clarity and high resolution, I go with the Panasonic.

      T.

    • #198262
      AvatarD0n
      Participant

      if you got a vg10 you don’t really need a d-slr, you need the Sony af converter to use the SONY (and Minolta) d-slr lenses and get your self a couple sony/minolta prime lenses…….

    • #198263
      AvatarJaimie
      Participant

      First off, thank you all for the kind words. I actually expected vitriol and argument since I was debunking some long-held beliefs.

      To address some of the comments and questions, David, I agree that not all lenses give good bokeh. I remember a Hasselblad lens which I think was 150mm that was incredible at middle apertures and I also believe that there is/was an 80mm Nikkor that’s generally regarded as wonderful. The Hass is a Zeiss lens so that sort of confirms your findings. For the youngsters in the gallery, these are all still camera lenses and some cost well over $1000 so they ought to be good.

      In my opinion great bokeh is art, it is hard to describe, but you know it when you see it and not everybody will agree on what is “good”.

      Reynand, I don’t know if sensors age, that is, deteriorate over time and/or with use and I am not sure what you mean by “better”. You CCD sensor probably is noisier than an equivalent CMOS sensor in low light, all other things being equal – which they seldom are. I have both CCD and CMOS video cameras and it seems that CMOS is about one f-stop more sensitive than CCD, but that is only a guess on my part. I use them interchangeably.

      The f1.2 lens will provide a brighter image than an f1.4 lens simply because it admits about 36% more light. Putting more light on the sensor will raise its signal-to-noise ratio which will be perceived as a “better” image.

      Unfortunately, newer often means better because technology is always advancing. Generally speaking in this business you get what you pay for and “killer” images – moving or still – cost a lot, but not always. Since you are never going to have the “best”, whatever that is, You use what you’ve got.

      Toby, everything you learned about still photography technology applies to video. A good picture is based more on how you treat the subject using light and shadow, focus, background etc than anything related to technology. A really good movie scene and a good still are visually the same thing. Of course, the goals are different – a still captures a moment and a movie captures an event. But they both must look good.

      The camcorder lenses have short focal lengths because the sensors are so small. A 1/3″ standard 4:3 DV sensor is about 0.2″ high and 0.264″ wide. That means to fill the screen top to bottom with the image of a 6′ (72″) man 10′ (120″) from the camera, the lens must project a image only 0.2″ high onto the sensor. The focal length required to do that is;

      Fl=(image height)(distance)/(subject height)

      Fl=(0.2)(120)/(72)=0.33″ which equals about 8mm. 8mm is a pretty short lens with a lot of DoF.

      Good luck! Personally, I believe it is better to concentrate on shooting to please your client, which may well be yourself, with your unique and personal treatment of the subject rather than worrying that there is some better equipment out there – there always is. Jaimie

    • #198264
      AvatarEarlC
      Member

      All makes, models, sizes and construct are basically tools, tools that work well in the hands of people who know how to use them, and apply their (and their tools’) strengths to the projects they want to create. There is NO other way to determine the extent and base of preference for any given style, make or model than to rent, test at the counter, or otherwise get your hands on the models and styles that most seem to suit your preferences and have a go at them. All the technical information is GREAT, nods to Jaime and others, but it still boils down to need, ability, personal desire and function. Oh, and costs when you’re (and most seem to be) on a TIGHT budget.

      While 1/4″ sensors are certainly capable in many instances, what I wanted when I asked was to spark comment, debate and information. It appears the post was successful in that endeavor. I personal have no desire to go that small in the sensor or chip department due to my broad production needs and diversified production business, but I have to say the pricing makes the consideration tempting.

    • #204515
      DanDan
      Participant

      Any professional should have the right tools. Back to what started of this thread: I begun with an AG-AC7 and I am still using it frequently. I've shot TV commercials that are incredibly sharp and converted them to 4:2:2 in post. I've spilled coffee on it a couple of times, and it travels with a light, a shotgun mic and a spare 4 hour battery.

       

      Zoomed in a little and with the right lighting, AG-AC7 will give you nice bokeh, take a look:

       

      It also has decent stabilization and macro:

       

      NO GREEN SCREEN: I gave up getting it to work with green screen, some things are just not for a prosumer camera. To get even lighting, no matter how you adjust exposure or iris, you need to add some watts to even out your background. When you add light, the green spills, plain and simple, and you will have a halo. I assume this may have been overcome if I had spaced wall, subject and camera a few more feet apart, but I don't have that luxury.

       

      Instead I put a Carl Zeiss F1:1.8 on a DSLR and turned all the lights down but one (50 watt) which lighted both the subject and the screen sufficiently, and I got amazing chromakey separation, out of one light pointed properly.

       

      The AG-AC7 is a great camera for the following reasons:

       

      Takes a beating, never heats up, 4 hr battery life, plenty of space to velcro a mixer and other tools to the body, you won't have a heart attack if you break it or lose it, has incredible sound compared to DSLRs (built-in mic will even zoom in with your visual zoom), and it's the first thing I grab before I fuss with which DSLRs, chargers, lenses, fliters, etc to take with me.

       

      I've inserted the footage from it into film taken via more expensive means, and nobody points to it saying "hey, that is not with a $4000 camera". Sure we all want a BMW, but in reality a Chevy goes 120 MPH just as well, and is cheaper to maintain.

       

      I know interlaced gets a bad rap, but most decent NLEs will convert to progressive or stich the interlace perfectly for you in post, so that's more an issue of learning the hidden output features of your editing software really well.

       

      If you see this ad output for TV (80Mbps, 4:2:2) you will notice absolutely no interlace lines. Again, straight out of the camera the interlace is horrible just like from any other 1080i camera. It's just knowing how to use the NLE to get the final output as good as it can possibly be.

      Below is the Sorensen compressed YouTUBE preview version.

       

       

      Most common mistake that give people poor footage (besides lighting considerations) is shooting one frame rate and resolution, then exporting in another frame rate and resolution, simply because the choice is not grayed out, and they end up with horrible footage. Then they turn around and blame it on the camera.

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