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Messages - privatebydesign

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1
Lighting / Re: Flash Zoom - Difference in Stops?
« on: July 23, 2014, 11:37:49 PM »
24mm - GN28m = f2.8 @ 10m and 100 iso
70mm - GN50m = f5.0 @ 10m and 100 iso
200mm - GN60m = f6.0 @ 10m and 100 iso

Therefore:-

 24mm - 70mm  = 1 & 2/3 stops
 70mm - 200mm = 1/2 stop

2
Canon EF Prime Lenses / Re: Canon EF 50mm f/1.2L USM
« on: July 23, 2014, 09:10:53 PM »
So the answer.

Three lenses, all Canon 50's the 1.8, the 1.4 and the 1.2L.

3
Lenses / Re: Something with 50mm L lens that make it different
« on: July 23, 2014, 09:10:07 PM »
So the answer.

Three lenses, all Canon 50's the 1.8, the 1.4 and the 1.2L.

4
EOS Bodies / Re: High Megapixel EOS on the Way as Mentioned by Canon
« on: July 23, 2014, 10:52:05 AM »
A shifted 17 gives the fov of an 11.5mm lens. A mythical 14mm TS-E lens would give a shifted fov of a 9.5mm lens.

5
Third Party Manufacturers / Re: New lamp, what to buy?
« on: July 23, 2014, 10:19:09 AM »

Viggo, I also have a pair of Einsteins and they are excellent, but I understand the import issues & costs.  I wanted to ask you about your need for HSS.  A few weeks ago I spent a good deal of time reading Paul Buff's thoughts on the use of HSS and why he will never implement the feature into his Einstein or other lights.  Essentially he feels that the power reduction and sync issues aren't worth it and you're better off adding more power to get to your camera's x-sync speed instead.  I can see both sides of the issue, but he had a lot of compelling arguments.  I can point you to some of the posts on his forum if you're interested.

I think one of the key points for HSS is the ability to select very narrow dof without resorting to variable PL filters which hurts focus etc. And that is Viggo's style, fast primes wide open.

I think Paul is being a little economical, PCB are happy to boast, very loudly, about the flash duration speed which is as dependent on low power settings as HSS is inefficient. There is no doubt there is a demand and interest in HSS for studio lights, and IGBT is the way to do it.
I agree, and you've probably noticed that there is more than just a little excitement about the new firmware for the Profoto B1 that allows HSS with the high-end Canon models...so obviously there is a need/market out there. 

On the subject of variable ND filters, I didn't like my time with them, and decided to keep using plain NDs that work out much better.

Yes the B1's are on my RADAR, though I recently got a crazy god deal on a two Einstein setup. I have some money set aside for a 1Ds MkIII upgrade, but nothing to spend it on, I thought the B1's were going to get it!

6
Third Party Manufacturers / Re: New lamp, what to buy?
« on: July 23, 2014, 10:03:43 AM »
Viggo, I also have a pair of Einsteins and they are excellent, but I understand the import issues & costs.  I wanted to ask you about your need for HSS.  A few weeks ago I spent a good deal of time reading Paul Buff's thoughts on the use of HSS and why he will never implement the feature into his Einstein or other lights.  Essentially he feels that the power reduction and sync issues aren't worth it and you're better off adding more power to get to your camera's x-sync speed instead.  I can see both sides of the issue, but he had a lot of compelling arguments.  I can point you to some of the posts on his forum if you're interested.

I think one of the key points for HSS is the ability to select very narrow dof without resorting to variable PL filters which hurts focus etc. And that is Viggo's style, fast primes wide open.

I think Paul is being a little economical, PCB are happy to boast, very loudly, about the flash duration speed which is as dependent on low power settings as HSS is inefficient. There is no doubt there is a demand and interest in HSS for studio lights, and IGBT is the way to do it.

7
Third Party Manufacturers / Re: New lamp, what to buy?
« on: July 23, 2014, 09:27:47 AM »
I dont know but A PCB Einstein @ 640 W/s would take atleast 6+ Speelites to get kinda close to the full power output. It would be the same with these if they are measures the same.
Thanks for the tip, but I can't buy Einstein, it's not sold here and I can't import due to importing rules, think it's about the lithium battery, and I think thy used to be only 120V , not 240V.

Not suggesting that you do buy an Einstein, though I recently got two and they are very good. But for the sake of accuracy, the Einstein doesn't have a battery in it and is allowed to be shipped anywhere worldwide with no restrictions (not saying there are not import regulations unrelated to batteries), also they run on any voltage from 95-250VAC 50-60Hz automatically, effectively you can plug them in anywhere in the world and they just work.

But international shipping is a pain and for service or warranty they have to go back to Tennessee.

As for the power output, as IMG_0001 said, the small flash GN only covers a very small area, the Godox has a much wider spread so actually puts out much more light. It is very difficult to compare flash power on specs, even when you use the same figure to do it. For instance if you compare a 1200WS Profoto to an older 2400WS Profoto in the same modifier the 1200 actually gives you one stop deeper dof because it is so much more efficient, WS refers to potential energy.

There is no accurate way of comparing flash output, there is no standard, without firing them next to each other in the same modifier. But the Godox will give you much more light output than the 600-EX-RT.

Thanks for he detailed info, great stuff. And I should've known, because it's just to compare my deep octa 70 cm to a cheap 70 cm octa off of eBay I have, the deep octa is MUCH better to reflect the light out of the octa.

Such a shame the Acute 600 doesn't do HSS, lol..

Hi Viggo, I added a bit to my earlier post that you might have missed that related to the printed specs on the Godox and its spread pattern.

Quote
Addendum: The Godox is rated at GN 52 with a circular beam spread of 65º, the 600-EX-RT is rated at GN60 with a rectangular beam pattern of a 200mm lens, or 12º. This means the area the Godox covers is around eight times bigger. In practice I'd expect the Godox to put out a couple of stops more power than both your 600's together.

8
Lenses / Re: Review: Sigma 12-24mm f/4.5-5.6 DG II HSM
« on: July 23, 2014, 09:20:48 AM »
Camera's are heading to higher and higher pixel counts, so they need sharper lenses.

Lenses should be designed and bought with photographers' needs, rather than sensor specs, in mind.

I very rarely print larger than A4, which means 99.9% of the time I could do with ~8MP at 300DPI + margin for crop, so the current crop of 18MP sensors is already an overkill for me.

I'm not going to complain about rise in sensor resolution, as disks & memory cards are getting larger, faster, and cheaper all the time, but why the hell would I spend money & effort on sharper lenses & better stabilization just to get those extra pixels I don't need to begin with?
Antona, you have a rare voice of reason around here and those are good points that most people should pay attention to when buying their equipment.

Agreed, and a point I have made many times myself, much to the derision of some of the forumistas. Do I detect a pattern?

Even if we all go to 4K TV's and monitors we are also only looking at 8MP.

9
Third Party Manufacturers / Re: New lamp, what to buy?
« on: July 23, 2014, 08:47:53 AM »
I dont know but A PCB Einstein @ 640 W/s would take atleast 6+ Speelites to get kinda close to the full power output. It would be the same with these if they are measures the same.
Thanks for the tip, but I can't buy Einstein, it's not sold here and I can't import due to importing rules, think it's about the lithium battery, and I think thy used to be only 120V , not 240V.

Not suggesting that you do buy an Einstein, though I recently got two and they are very good. But for the sake of accuracy, the Einstein doesn't have a battery in it and is allowed to be shipped anywhere worldwide with no restrictions (not saying there are not import regulations unrelated to batteries), also they run on any voltage from 95-250VAC 50-60Hz automatically, effectively you can plug them in anywhere in the world and they just work.

But international shipping is a pain and for service or warranty they have to go back to Tennessee and the Einstein also doesn't do HSS.


As for the power output, as IMG_0001 said, the small flash GN only covers a very small area, the Godox has a much wider spread so actually puts out much more light. It is very difficult to compare flash power on specs, even when you use the same figure to do it. For instance if you compare a 1200WS Profoto to an older 2400WS Profoto in the same modifier the 1200 actually gives you one stop deeper dof because it is so much more efficient, WS refers to potential energy.

There is no accurate way of comparing flash output, there is no standard, without firing them next to each other in the same modifier. But the Godox will give you much more light output than the 600-EX-RT.

Addendum: The Godox is rated at GN 52 with a circular beam spread of 65º, the 600-EX-RT is rated at GN60 with a rectangular beam pattern of a 200mm lens, or 12º. This means the area the Godox covers is around eight times bigger. In practice I'd expect the Godox to put out a couple of stops more power than both your 600's together.

10
Lenses / Re: Something with 50mm L lens that make it different
« on: July 22, 2014, 04:51:34 PM »
You seem to be missing the point, if the screen isn't calibrated to the same colour as the original subjects illuminant then the colours can't match

We're talking about two different things.
I'm just saying that the computer can tell you what you are looking at in that moment, what flavour of light is coming out of the screen, which is what many people seem to debate. I'm not debating the accuracy of the image capture system.

I don't think we are.

As a purely hypothetical point you are saying that one section of the flower reflects a specific wavelength of light, and that one screen pixel can emit that same single wavelength, here we agree, where we differ is you say the whole flower will look identical to the screen, I am saying it won't unless the screen is specifically calibrated to every image illuminant on the fly. One tone, hue, and saturation of the flower and screen might "match", but the rest won't, they will be shifted by the screen calibration, go to "correct" another pixel for tone, hue, and saturation and the first will shift.

In this hypothetical theoretical situation, the flower and screen can't possibly reflect and emit the same light wavelengths unless the screen calibration and spectral characteristics are exactly the same as the flowers illuminant spectral characteristics, for every single shot. That is not how it works. You might think that a colour picker registering 146,37,101 would be the same colour everywhere, but it isn't.

You cannot get around the screen calibration limitation, more specifically, you can't get around the difference between the screens spectral characteristics and the image illuminations spectral characteristics, in talking about accurate colours you can't ignore the inaccuracies and limitations of the image capture and reproduction systems.


11
Lenses / Re: Something with 50mm L lens that make it different
« on: July 22, 2014, 04:11:40 PM »
But a scalpel is no good if you are cutting bread, and most of us cut bread a lot more often than we perform operations, to most of us a scalpel is dead weight and of no practical use, however a good surgeon can perform most operations with a bread knife.

Agree with the rest, but I don't believe a good surgeon (even the greatest surgeon) can perform even the most basic of operations with a bread knife, or even with a dull scalpel for that matter (I have to do surgeries for a living ;) ). There is something about the right tool for the job.

You haven't watched enough "The Walking Dead" :-) Or how about the various emergency tracheotomies done with a ball pen?

Cut me a bit of slack with my metaphor!

12
Lenses / Re: Something with 50mm L lens that make it different
« on: July 22, 2014, 02:44:41 PM »
PBD,
No, I didn't cheat, there is seriously no fun in cheating.  There were a few where I had really no idea and had to guess.  It will be interesting to see the results to see if what I got correct was based on what I thought, or if I got lucky.

You are very well mannered about all of this, I will give you that.  Even in the face of people getting upset with it.  You dodged my questions though about if you think you could see the differences in out of the camera images?

Tom

I didn't intentionally dodge anything, just missed a few bits here and there.

The question of noticing differences out of camera is interesting, and obviously the backbone of my post in the other thread, which started this, was that we do so much post processing virtually all intrinsic lens characteristics are masked, and almost all of us do some post processing.

I was watching a Joel Grimes video the other day and he doesn't care what lens or even camera he uses, he will mix Pentax 645D and Canon 5D MkIII files shot with a variety of lenses for his composites, mostly the 24-70 f2.8 MkII always at f7.1 and the 24 TS-E with the Canon, and he is a sharpness freak. But he gets all the images to have the same colour and contrast characteristics. Whether we like it or not it is predominately our post handling of the captured images that makes the image, even a simple crop can change an f1.4 shot to an f1.2 shot!

Do I think I could tell the differences in ooc images? Like most of you, sometimes yes but most times no, I certainly profess no special powers! I found with the EF50 1.2L that there was a very narrow window of usability where it shone, and if you shoot predominantly in that window then the lens is very good. But a scalpel is no good if you are cutting bread, and most of us cut bread a lot more often than we perform operations, to most of us a scalpel is dead weight and of no practical use, however a good surgeon can perform most operations with a bread knife.

I know which images were shot with which lens, and I have slightly bigger copies of them, but even I, with a relatively keen eye and experience of all the lenses used and literally thousands of 50 f1.4 images, don't believe some of them.

13
Lenses / Re: Something with 50mm L lens that make it different
« on: July 22, 2014, 01:39:35 PM »
talicoa,

Nice try, you did far and away the best and assuming you didn't cheat you beat the probability of guessing randomly by a few images.

You got 12 out of 24 :-) 50% right, 50% wrong.

14
Lenses / Re: Review: Sigma 12-24mm f/4.5-5.6 DG II HSM
« on: July 22, 2014, 10:08:18 AM »
One of my mentors, an incredible photographer at the very top of his niche in the world who was tragically killed on a shoot, Marc Paris, used the 12-24 almost exclusively. He had the money to buy pretty much any lens and camera made but he swore by that 12-24 on his 5D MkII.

If you look in any high end motor yacht magazine from two to ten years ago, chances are there is a Marc Paris photo shoot in there, often times more than one. Every interior shot was done with that Sigma 12-24. And if you like the lighting on those interior shots know that he did it all with three flashlights (torches) and a mixture of ambient and light painting.

A true master of light and sorely missed.

15
Third Party Manufacturers / Re: Adopting a MF system.
« on: July 22, 2014, 10:04:23 AM »
Absolutely serious question:
What value do you see in buying and using this equipment? Those Kodak backs are very old, and have a high crop factor.

Is it the resolution? If that's the case, I promise you you'd be better off buying a Nikon D810, which would be better at pretty much everything. Focus? Check. Resolution? In the real world, check. Dynamic range? Oh my God, yes. Lens selection? By a country mile. Shallow DOF control? Oh yes.

I can think of no logical reason to buy into this system.

If you can't think of a logical reason to buy one, then you haven't used one. Both David Hobby (strobist) and Zac Arias (One Light) who are well known for their "economy" have both bought into MF digital in the last couple of years. The sensors might be cropped from film sizes but they are still at least twice the size of 135, that is similar to the difference between crop and ff cameras, plus the 16 bit files, plus the AA filter etc etc.

If you can see the difference between crop cameras and ff cameras and want "more", medium format delivers in spades. It also introduces a completely different work vibe, there is a palpable difference between shooting with a 135 format and MF, it adds a quintessential nuance to the environment. Think things like a Bentley door closing, the sound of a Profoto pack going off to an Alien Bee, stuff like that, to most people those things are of low value, to a few they are everything.

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