The Panasonic TM900 Users Thread

[Phil Lee]

Hi

The manual "iris" control is limited to a set of pre-defined combinations of f stop and gain. The settings are f4.0, f3.4, f2.8, f2.4, f2.0, f1.7, open, open w/ 3db gain, open w/ 6db gain, ... all the way up to 18db gain. Notice that no gain is ever applied until the iris is completely open (f1.5). This means, for example, that you can't select f2.8 with 12db gain to increase depth of field at the cost of noise. You are stuck with the lower f-stop equivalent of f1.5 with 0 gain.

You should be able to go from f16 all the way to open.

The gain setting only available after the iris is fully open is never going to change if history is anything to go by as it's been like that on consumer aimed Panasonic camcorders for years and years, the same regarding no aperture priority. While it would take nothing to add these features (just software changes) I suspect they don't simply to distinguish their consumer and pro-consumer camcorders.

Regards

Phil

[Roger Shealy]

Time for a TM900 Magic Lantern Hack!

[Alan Christensen]

Thanks to Phil for the clarification on TM900 f-stops. I was confused on this because of what I had observed when taking pictures of a TV resolution chart for my lens tests. I had the camera in picture mode (rather than video mode). I would turn on the camera, switch off IA, then vary the shutter between 1/750 of a second and 1/15 of a second. I really wanted to see the effects of f-stop on lens resolution, but decided that the easiest way was to simply vary the shutter speed thereby forcing the camera to use progressively higher f-stops to keep the chart properly exposed. I knew that I could pull the f-stop and shutter speed info out from the EXIF info later when analyzing the pictures.

However, I quickly noticed that the camera would never pick an f-stop greater than 4.0, even when the picture started overexposing badly. The f-stop would slowly increase as I decreased the shutter speed, but the f-stop would never progress past 4.0. I incorrectly assumed that the camera did not have f-stops above this figure.

Since seeing Phil's post I went back and did some more experiments. As Phil pointed out the camera has f-stops all the way up to f16. In video mode the camera will use all the available f-stops when in shutter priority mode. However, in picture mode the f-stop will never go above f4 unless you force it there manually by using the iris adjustment. I suppose the Panasonic engineers decided that no one would ever knowingly want to do this in automatic exposure mode, so they enforced this limitation. It is kind of nice as you do notice the picture suddenly overexpose as you ratchet down the shutter speed. This warning makes you realize that you should probably pick a faster shutter to get a good picture. For some rare situation where you might actually want to take a picture of a bright scene at f8 1/15sec, you can get there by setting the shutter first, then using the iris control to manually adjust the iris to f8.

[Dave Jervis]

Alan, I use a TM700, but what you describe is familiar to me... these cameras appear to be designed to avoid using small apertures in auto mode even though " f16 " is available in manual mode. I think this f4 limit is probably to avoid the diffraction degradation (softening) that small apertures can cause, and this is worst on cameras with small sensors with their correspondingly shorter focal length lenses. (Excessively large depth of field can sometimes be problematic as well I believe.)

While the f number conventionally refers to the lens aperture alone, this is not the case for these cameras. The lens has an iris (well, a diamond shaped variable aperture to be more accurate) but it also has some automatic ND filters which are introduced gradually to control exposure without letting the aperture become too small. When the camera is telling you it is at f 2 it probably means it. When it tells you it is at f 8 it probably means it is at something like f 4 but with ND filters in the light path. (...I don't have precise details so cannot say at what stop these filters start to swing in, and it may change with zoom angle as well...) The f number displayed on the camera seems to be more a representation of how much light the lens is letting through rather than purely the size of the aperture. (Both Claire an I have observed this on our cameras, and a highly regarded camera expert on another forum has explained to us how and why Panasonic use this system.)

I am of the opinion that these cameras, in fully auto mode, resort to controlling exposure with shorter shutter speeds when the "f number" gets in the f 4 - f 5.6 range. If you force the shutter to 1/50 or 1/60 but leave the "iris" in auto the camera will still not stop down below that f 4 - f 5.6 range.... unless you go to full manual. I think this is what is causing the over exposure you describe.

On the TM700 this happens in video mode, maybe a bit different on the 900 series.....

dave

[Phil Lee]

Hi

A lot of video cameras tend to work this way with ND filters. I think as well using an ND filter in the sweet spot must help avoid visible varying depths of field as the camera auto exposes using the iris, which might look like focus problems on playback or be distracting.

It seems the ND filter trick is quick common on consumer cams.

Regards

Phil

[Adrian Lepki]

Hello TM900 users,

this is a great thread, as is this little camera whose ownership I took a few weeks ago :)
Due to my big hands I've accessorized it with a pistol grip. I also use Audio-Technica PRO 24-CM camcorder mic. The red rubber band on the lens ring is there to improve the ring control.

PRO 24-CM Stereo Condenser Microphone

Pistol grip


Cheers, Adrian

[Roger Shealy]

Got to use the TM900 on real subjects for the first time last week in the Moab desert region of Utah. Here's the result with some 7D stills thrown in:

20110601 Utah and Moab Trip on Vimeo

Nice little cam.

[Colin Rowe]

Thanks Roger, watching that made a lovely start to the day. What spectacular scenery. I was thinking of going to Dartmoor to take some shots. You have inspired me to do so ( when this damn rain stops). "Flaming June" I dont think so.

[Roger Shealy]

Colin,

I hope you do go to Dartmoor and share the results. Hiking with a 1 pound camera that takes quality footage is a very nice thing compared to lugging a full sized camera!

[Colin Rowe]

Still raining, and getting worse over the weekend !!!!!!!!!!!! I agree, the benefit of having such a small camera, that takes amazing footage is so handy. I am getting far more shots of family events, grand children and such. The EX1 stays in its case now, only comes out for work

[Andy Wilkinson]

Hi all,

After a bit of playing around I've found another solution for using the Rode Videomic Pro on the TM900 which enables it to wear its freebie Rode Deadcat and not appear in shot when on full wide on the Panny. This is an alternative way of keeping the deadcat out of shot to mounting the VMP body in the spare Invision Video mount that I have.

It's a 10cm Rycote Hot Shoe Extension (Code 037303). See the Rycote website for full details.

I actually bought this Hot Shoe Extension thinking I'd fit it at 90 degrees to the direction the camera is pointing in (i.e. with it extending out in the opposite direction to the LCD) and then mount the Rode VMP on the end of it in order to get an increased distance from the lens.

However, I found that since the Rode's metal shoe is rectangular, not square, I'd need to remove a few mm off the front and back of it to be able to do this...as there is no point having a shotgun pointing at 90 degrees to the direction that the camera is !!!! I may well get the file out again and do it to give me much greater flexibility in how I mount it... but will ponder it for a while before I do anything too destructive to the VMP's shoe in case I think of a better way.

Certainly, with the Rycote rail in the longways direction it's easy to mount the Rode VMP further back and out of sight of the lens, yet you can still get your fingers around the TM900's body and use it hand held - just - as long as your fingers are not too fat that is! (mine squeeze through nice and snugly!) Snaps below.

By the way Colin, I'm same as you. TM900 comes out to play a lot but the EX3 gets used mainly just for work stuff now!

[Roger Shealy]

By the way, I used a linear polarizer on the TM900 and it worked great, no interference with metering that I could tell.

[Keith Moreau]

Originally Posted by Andy Wilkinson

Hi all,
It's a 10cm Rycote Hot Shoe Extension (Code 037303). See the Rycote website for full details.

Andy, great minds think alike :) I've done the same exact thing with the hotshoe mount, the VideoMic Pro with freebee softie and the Rycote extension. It works well and the frame is clear. The mic adds quite a bit of volume (space not audio) to the whole TM900, of which it's charms are that it is so small and high quality, but it's all still very light weight with the mic and Rycote rig.

Did you ever mention your picture settings for getting the best high latitude images with the TM900? I've been using the intelligent contrast and then color correcting but since it has to be in auto exposure mode I'm noticing a bit of flickering during some shots shots while the TM900 is adjusting auto so I'm going to go to full manual when I can help it. I was liking the intelligent contrast though because I could really get a range of maybe 13 stops in a scene without blowing out or crushing, with the picture control down to -1 or -2.

I've done a bit of experimenting with manual exposure and the blacks do get a bit crushed but there isn't a lot of noise down there. I wish the color matrix was a bit more tunable though.

I have the TM700 as well and I think the TM900 has greater range and less noise. Thanks to you for starting this thread and for everybody else for sharing.

-Keith

[Peter Riding]

The Rycote rail is rather expensive for what it is and there are now a lot of much cheaper choices on Ebay now that lots of people are looking for solutions to equiping their dSLRs for video.

In particular search on c shaped flash bracket as these will enable you to add a microphone and a video light at the same time should you wish.

Don't use the c bracket "as is", just use the "c" bit. And attach it direct to the hotshoe using the same type of double screw adapter shown in Andy's photos (which are also readily available. You could of course attach it to the camcorder's tripod screw but you would then loose the ability to attach the whole thing to a tripod plate or ballhead unless also using a further suitable male/female screw; that would however relieve weight stress on the cam's hotshoe.

Pete

[Keith Moreau]

Yes, Peter, you're quite right. In fact I wound up not using the Rycote hotshoe extension for much else, it was just lying around and that's why I'm using it on the TM900 . There are items very much like this that come with light sets, like the Sima LED lights, and these SIMA lights are sometimes like $10, you could get 4 lights with brackets for the cost of the way overpriced Rycote product. I have several Rycote items, they are well made and sometimes a good deal for the quality, in this case it's an accessory that's in many less expensive forms elsewhere.