July 25, 2014, 05:47:39 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - CJRodgers

Pages: 1 ... 9 10 [11] 12 13 14
Lenses / Re: Zeiss 35 f/1.4 Available
« on: May 18, 2011, 04:39:13 AM »
I think this lens would be amazing, but i think it needs to be £400 cheaper.

EOS Bodies / Re: 26.4mp 5D Mark III Mid-year? [CR1]
« on: April 20, 2011, 04:35:16 AM »
If the 5d mkiii had noise improvement would it make using f2.8 better for low light as you can use higher ISO?

Yes, but at some point there's a limit. There are two parts of noise, the camera's own ("read noise") and noise in light itself (photon shot noise). Most people forget about shot noise and assume that noise at high ISO is just contributed from the camera electronics. Actually, the shot noise is often dominating (I have not found out where the line goes, but perhaps some other reader of this forum knows).

The signal-to-noise ratio of the shot noise reduces the more light you gather, that is lower shutter speeds, larger apertures, larger sensor size. That is you always want to gather as much light as possible, to be able to use as low ISO as possible.

One other factor to know about is that not all f2.8 are the same concerning light transmission, and it is not only about vignetting. There can be quite large differences between lenses, some lenses can transmit a half stop less light than others at the same aperture. For example the 24-70 f/2.8 has a transmission corresponding to ~f/3.4 while a large aperture prime lens set at f/2.8 typically has much better transmission (did not find an example measurement unfortunately, but it can easily be observed in testing).

Yea i would love to know what the theortical best the 24-70L could be. This would be an ideal lens if it could handle low light just a bit better. So do you think no matter how good the noise handling in the camera, this lens could never be fast enough for really low light.

EOS Bodies / Re: 26.4mp 5D Mark III Mid-year? [CR1]
« on: April 20, 2011, 03:10:50 AM »
If the 5d mkiii had noise improvement would it make using f2.8 better for low light as you can use higher ISO?

EOS Bodies / Re: LED light panels
« on: April 19, 2011, 07:13:53 AM »
brilliant thanks!,

and @lawliet, sorry didnt read your first post! sounds great for a flash, those leds are very powerful.

EOS Bodies / Re: LED light panels
« on: April 19, 2011, 04:37:59 AM »

Can you give some details of the power supply and construction?  What did it cost to put it together?

11 coulums of 9 LEDs each, in a half inch grid. A metal core PCB for good heat dissipation, for usage as a flash its thermal capacity would be enough, as a video light two heat sinks intended for high end graphics cards helped...500W for 1µs is simpler then 100W for indefinite time.
Groups of 3 LEDs each get their own driver, for a forward voltage of about 10V, a powerFET as a constant current source, powered by a 12V lead acid battery, buffer caps and charging current limiter don't do a thing for constant illumination.
As a video light its a wasteful design, driving the LEDs at just about 1/4 their rated power because they are to tightly packed and using linear regulation - but thats just a secondary use... :)

Overall costs in the 1500€/$ range, but if you want just a video light you could get away with the new XM-L LEDs and about 25€/$ per 100W of tungsten filament. Thats if you buy enough parts to get past the markup of low volume dealers.

For inspiration: take a look at a Fenix TK35/41 for what a single Cree XM-L can do, or a TK45 to give you an impression of 3 XP-Gs. Both give you ~3 stops more then the average video light. 8)

Sorry i didnt fully follow this, is this just for a flash or for continuous use aswell? Im looking to make a continuous LED panel for lighting during filming.

What cd rating where these LEDs? Also what colour temp? Also have you found anything that suggests how to place teh leds for maximum coverage whilst mainting brightness. For example would a ring arrangement be better than a grid of LEDs?

I have found some ultra bright LEDs that cost about £1 each, so i dont think the whole project should cost more than £150 hopefully including battery although i need to do some research on that.

I havent worked out values im just collecting ideas. But mine will definately be for a rechargeable battery only as i dont want the cost or weight of a transformer, plug, rectifier, extra fuses, more capes etc that would all come with using mains supply.

LEDs and LED drivers are dirt cheap, and for the powersupply i will just a regulator, something like the lm317 as its adjustable but i need to check the amp rating. Ill use some big caps for smoothing, something like 100uf electrolytic and some diodes such as 1n4004 to protect the circuit from being reversed (battery connected the wrong way around)

I litterally just need somthing that inicates the sort of brightness i need and the best layout. Ill go have a look at the stuff out there i guess and just copy their specs?

..I might make it usuable with mains as a seperate junction box, fitting the transformer etc in the junction box rather than with the LED panel.

Lenses / Re: Canon 24mm 1.4 distorting faces for close ups.
« on: April 15, 2011, 03:06:18 PM »
Thanks for the advice. Again, i have no dslr, just a massive passion for a long time. I really want a FF camera and i only want to get decent glass. Its a lot of money and i want to get the majority of it right first time if thats possible. I have a 4.5 k budget but want to leave some money for lighting. I dont want to grow out of things quickly so i want to buy what i think ill need and learn how to use it properly. If i have any spare ill get more glass after that. I want to do band photos and music videes and live gigs. Then mayb move into wedding stuff many many many years down the line if i get good enough.

Lenses / Re: Canon 24mm 1.4 distorting faces for close ups.
« on: April 15, 2011, 12:08:58 PM »
Oh rite, i read a couple of reviews saying the zeiss was a fair bit better than the canon 50mm 1.4 but not a touch on the 1.2 (which i cant afford). Ill have to read a few more then! It is cheaper so id rather have it!

Ideally id like the 24-70 if anyone could tell me what the limits of f2.8 is before i have to put the ISO up to far. Id like to do low light stuff. But the term low light isnt exactly defined!


EOS Bodies / LED light panels
« on: April 15, 2011, 11:37:34 AM »
If you were to buy an LED light panel for continous lighting whilst filming,  what would be your minium requirments for it. I am thinking of building one but i want to know what colour temp and brightness are acceptable. Dont want to go through all the effort to find out its average! HA.

Also has anyone got any experience with filming with LEDs in in low light? Are they up to the job?


Lenses / Re: Canon 24mm 1.4 distorting faces for close ups.
« on: April 15, 2011, 11:34:30 AM »
Thanks for all the replies, really helpful. I didnt realise an extender would double the aperture aswell? Thanks for that. Also after a couple of replies i think that possibly looking at 24mm portraits on flickr i didnt realise what i was looking for with distortion. Your correct, i dont think her nose is that big!

And i meant the 50mm 1.4 ziess. I wanted a 2x extender on a 24mm to get 50mm ish, although it would have been cheaper to use an extender than buy a second lens. I think i can just about afford a 24mm and a 50mm zeiss.

I did want the 24-70mm 2.8 but i know a lot of stuff i want to do is low light and im not sure where the line ends really as to what f2.8 can cope with?

Yea i have a seperate small lighting budget. I want a 580ex or ill wait and see if a new version with a video mode comes out. Other than that i wanted some cool continous lights but i cant really find much. I might have to build my own LED panel i guess!

Lenses / Re: Canon 24mm 1.4 distorting faces for close ups.
« on: April 15, 2011, 07:32:36 AM »
ah ok so ill have to get the zeiss then, was just trying to save some money as i would probably buy a 2x extender at some point anyways! thanks

Lenses / Canon 24mm 1.4 distorting faces for close ups.
« on: April 15, 2011, 07:19:41 AM »

I only really have enough money to buy one lens to begin with on a 5dmkii and i decided i wanted a fast wide lens for photos such as group photos and events and filming. However I am reading that the 24mm will disort faces for portraits. I have two questions,

1/ how close do you have to be to distort faces because this sort of portrait looks fine to me? http://www.flickr.com/photos/shaynabatya/4060563740/

2/ if i used a 2x extender would this solve my problems? I cant find any examples of anyone using an extender on a wide angle lens so i am wondering if anyone has experience with this? or i could possibly afford the zeiss 1.4 if the quality of the 24mm and  2x extender is no good? What would you recommend?

Thanks for you help!

EOS Bodies / Re: Canon Updates E1 Plugin for FCP.
« on: April 08, 2011, 08:27:30 AM »
Oh rite, is this part of the T&C that you cant use it to make any money? Makes sense i guess. No idea how anyone would ever find out though if you worked from home?

EOS Bodies / Re: Canon Updates E1 Plugin for FCP.
« on: April 08, 2011, 08:16:37 AM »
Yea i have been thinking of getting CS5 for a while now. Might have to use my brothers student accuount to get it cheap, i cant afford it otherwise lol!

EOS Bodies / Re: Canon Updates E1 Plugin for FCP.
« on: April 08, 2011, 07:05:55 AM »
Can you get final cut pro for PC nowadays or or is this only going to benefit mac users? Im buying bits to build a PC, would be gutted if all the new cool stuff was only for apple.

Or if i build my PC with latest sandy bridge chip should the quick sync function do the same thing pretty much? ie quick encoding?

Was going to get the latest adobe suite. Would anyone recommend it?

EOS Bodies / Re: What do you want from the 5D mk III
« on: April 07, 2011, 02:56:28 PM »

Yea a followfocus would be awesome. I have seen the electircal one from Oki, i think thats the name.

Any info on decent full rigs too would be great! Really appreciate any thoughts, message me if its not appropriate here! Thanks

Pages: 1 ... 9 10 [11] 12 13 14