Latitude of HD FX1
 

Has any one tested the LATITUDE of FX1. I read at another forum that FX1 has only 5 stops of latitude comparing with DVX100A's 7 stops?

yikes!!!

OK. I know I am a beginner. But I looked up that word in the FX1 manual, and it wasn't even there.

Please...

What is Latitude?

It is too general to Google it successfully.

Film has a latitude of about 10-11 stops. Most video cams have a latitude of about 8 stops.

Latitude is the ability of the media to record a range of brightness values from full shadow to bright white. At 11 f/stops, film can do a pretty good job. Digital sensors, at 8 stops, require fill lighting to keep from either blowing out the whites or muddying the shadows. At 5 stops of latitude, I would consider the media unuseable at everything but studio conditions. Even at that, images would be flat without contrast.

I know that it does GREAT in low light, my experience.

I honestly doubt that great low light performance can come from this camera. See here for evidence:

http://www.dvxuser.com/cgi-bin/DVX2/YaBB.pl?board=sony;action=display;num=1103104690;start=30#30

The FX1 has noticably less latitude than either the XL2 or DVX as would be expected by technical specs.

It's not a question of low light performance. It's a matter of being able to adequately resolve a wide range of exposures, ranging from shadows to brightly lit; and, all within the same frame..

<<<-- Originally posted by Aaron Shaw : I honestly doubt that great low light performance can come from this camera. See here for evidence:

http://www.dvxuser.com/cgi-bin/DVX2/YaBB.pl?board=sony;action=display;num=1103104690;start=30#30

The FX1 has noticably less latitude than either the XL2 or DVX as would be expected by technical specs. -->>>

He obviously had it in an auto mode and had a picture profile. I have this cam and can attest that it is as good if not better than a vx2100 for low light. Granted its still not as good as film- maybe someday we can get that, but in the meantime im happy with what it does.

No, the test was specifically set up scientifically. Read the whole thread and you will see.

Barry knows what he is doing. Many can attest to that. He is a very impartial voice - which many people recognize.

Bill, I do understand that. My comment was merely directed at the post which claimed it had amazing low light capabilities not the dynamic range discussion. Sorry I didn't make that clear - my fault.

the following test from Kerr Cooks site (10/28/04) could have been performed a lot better wrt lighting and correct alignment etc, but has the benefit that anyone can repeat it for latitude testing

http://www.digitalcamerainfo.com/ker...B--60thsec.zip

just look at the 11 distinct and well defined grayscale...

I would add, that so that we can have a common base any testing should, in all fairness, be conducted so that anyone can independently verify the findings. That to my mind means standard charts etc with a detailed report of the camera settings

cool pic John Jay, that is pretty cool how you can see the bumps in the cardboard of the color card...never seen that with a DV cam!

Nope. The camera was set on full manual at all times, with careful attention paid to all settings. All settings were verbally slated on the tape (i.e., f-stop, whether the camera was in Cinematone Gamma or not, what CineFrame setting was used if any, etc.) All image control settings were at the middle, off, or default settings on all cameras.

The FX1 is not in the same league as the VX2100 in low light sensitivity. It's usually a full stop slower than the XL2, and two to three stops slower than a DVX, and the VX2100 is even a little more sensitive than the DVX. It does have a relatively noiseless signal though, I will say that for it.

I've got CamAligns, Accu-Charts, EIA's, MacBeth's, all on all three cameras with notations as to what was what. I don't have all the tapes here - this test was conducted in conjunction with someone else, so I may not have all the tapes with me now. I've found the XL2 and FX1 CamAligns though. You can see those here:

XL2 CamAlign: http://www.icexpo.com/XL2-CamAlign-16x9-24P.JPG

FX1 CamAlign: http://www.icexpo.com/FX1-HDV-60i-CamAlign.JPG

Both cameras are easily capable of resolving the entire grayscale section without crushing to black or blowing out whites. The CamAlign is a nice chart but it doesn't really stress their full latitude capability.

<<<-- Originally posted by Bill Ravens : Film has a latitude of about 10-11 stops. Most video cams have a latitude of about 8 stops.

Latitude is the ability of the media to record a range of brightness values from full shadow to bright white. At 11 f/stops, film can do a pretty good job. Digital sensors, at 8 stops, require fill lighting to keep from either blowing out the whites or muddying the shadows. At 5 stops of latitude, I would consider the media unuseable at everything but studio conditions. Even at that, images would be flat without contrast. -->>>

I would put film in the 12-14 stops range.

Carlos

Thanks for the response.

When the latitude is low the images become contrasty, not flat.
The sample footages I have seen so far (Kaku's and others) did not show that the cam is that low in latitude. The early demo from the Taiwanese site showed lot of latitude. From dark shadows to the details in the sky. (The temple shot)

I am confused.

<<<-- Originally posted by John Jay : the following test from Kerr Cooks site (10/28/04) could have been performed a lot better wrt lighting and correct alignment -->>>

Yeah.... I'm wondering why we see the noticeable barrell distortion? Was it shot up close with full wide zoom?

<<<-- Originally posted by Barry Green :Both cameras are easily capable of resolving the entire grayscale section without crushing to black or blowing out whites. The CamAlign is a nice chart but it doesn't really stress their full latitude capability. -->>>

My understanding of the chart goes like this:

If you arrange the lighting/exposure such that the white part of the greyscale is just on 100% zebra and two cams show similar performance down to the black, then the latitude of both cams is within 8/10 ths of a stop of each other - (8 bit video with a 10 step greyscale).

<<<-- Originally posted by Boyd Ostroff :

Yeah.... I'm wondering why we see the noticeable barrell distortion? Was it shot up close with full wide zoom? -->>>

Yup, straight from the ministry of silly test charts :)

Well, file that one under "duh, I'm a dope!" :) Yes I should have done that.

I shall retest as soon as I can and use a waveform to make sure that all three cameras are peaking on the whitest chip. It'll probably be at least a week though before I can get to it.

I do have a DV Rack exposure chart here, I'll test it with my DVX and see if its grayscale is deep enough to stress the DVX, and if so, I could use that to retest with an FX1 sooner...

we're on the same page then :)

All right, I've got a solution that should work, using the DV Rack exposure chart -- I may not be able to get both ends of the gray scale to fall out of latitude in the same shot, but: setting the light such that the darkest chip responds at 50IRE should get the lightest chips to severely blow out to white, and then doing a second exposure by setting the lightest chip to respond at 50 IRE should get the darkest chips to crush to black. Then, by monitoring the chips with a spotmeter, I should be able to determine how many stops over/under a 50-IRE exposure each camera is able to resolve.

Don't know when I'll get to test it, should be in the next week or so.