Approve the Cookies
This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and our Privacy Policy.
OK
Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Guest
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS General Gear Talk Flash and Studio Lighting 
Thread started 28 May 2018 (Monday) 18:00
Search threadPrev/next
sponsored links
(this ad will go away when you log in as a registered member)

6 stop ND filter - focusing issues

 
nixland
Senior Member
537 posts
Gallery: 3 photos
Likes: 199
Joined Apr 2009
     
May 29, 2018 23:11 |  #16

Yes I think there's a misunderstanding here :)
Agreed, the strobe does not loose power.

MalVeauX wrote in post #18635429 (external link)

nixland wrote in post #18635419 (external link)

MalVeauX wrote in post #18635075 (external link)
That said, some long burn HSS methods, the output is only dropped by 1 stop or so, and it doesn't matter if you sync at 1/500s or 1/8000s.

That's not possible at all.
Because the light power is constant (let say you set the power of the long burn/hypersync or whatever the name) and act like continues light (just like ambient light) and the exposure time is very shorter at higher shutter speed.
You can not defy physics.

Where did you get that info?

Maybe we're misunderstanding each other. If you're long burn HSS at 1/1 power (losing a stop or so, to the fact that you're using long burn HSS instead of normal sync), and you set your shutter to 1/500s and 1/8000s, do you think you lose any power output from the light? You don't. The light didn't change power. The camera's exposure will be different. But the light's output is not. No defying of physics. The point is, just because the HSS method is synced doesn't mean the light itself loses out on more power just because you're syncing at a shorter duration. There seems to be a confusion between light output power, and what is exposed on the camera sensor; so hopefully this clarifies that for you. This confusion is because of the original topic referred to the strobe losing power output, with a shorter duration synch speed progressively. This is why I pointed out that some HSS methods are different in this respect.

Very best,




  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)
Van ­ Gogh
THREAD ­ STARTER
Goldmember
Avatar
1,330 posts
Gallery: 118 photos
Best ofs: 5
Likes: 381
Joined Jun 2013
Location: Toronto, Canada
Post edited over 2 years ago by Van Gogh. (2 edits in all)
     
May 30, 2018 13:49 |  #17

Speaking of physics, this is what I think.
I just imagined this in my head, so not sure it is true or not.

As per my "physics imagination", using higher shutter speeds all else being equal will result in 2 things.
1) Ambient exposure will obviously decrease as higher shutter speed, but to offset it you just use higher ISO or wider aperture opening.

2) Flash power will decrease as you use higher shutter speed if you keep ISO/Aperture the same. Why? Because when shutter speed is higher in HSS, the shutter curtain that moves over the sensor has even a smaller opening. The result is that each portion of sensor is exposed for a shorter period of time to the constant source of light. In HSS flash is not a burst of light anymore, it is more like a constant light source, just like the ambient light. So, when in HSS, the faster the shutter speed the weaker the flash total output. (In fact a more correct description would be the sensor catches less of the flash light, in fact flash power stays the same in HSS over the whole range of shutter speeds, its only because shutter moves faster with faster shutter speeds camera sees less of flash light).

3) No, but what really matters at the end of the day is flash power vs ambient power correlation when we use flash outside. Yes, when using higher shutter speed the camera sees less of flash light output, but with higher shutter speed camera also sees less of ambient output too. Bottom line emans that as you move higher and higher in shutter speed in HSS, camera sees less of both ambient as well as flash exposure. So, perceived power contribution of flash vs ambient stays the same.

4) Bottom line is flash power doesn't decrease when compared to ambient power when moving higher and higher in shutter speed when in HSS mode. Hence, there is no need to use an ND filter to stay at the lower end of shutter speeds in HSS mode.

5) The question comes down too weather one should use a strong ND filter to stay out of HSS mode altogether, but this is another question I will think of next.

Now, is my logic correct or am I on wrong path?


Camera - 2x5Dmk3, C100 mkii, 70D, 60D
Lenses - 24-70mm f2.8L II, 70-200mm f2.8L IS ii, 85mm f1.2L II, 35mm f1.4 ART, 100mm f/2.8L Macro IS
Lighting - 3 x 600EX RT's, Printer - Epson 3880

  
  LOG IN TO REPLY
ShutterKlick
Senior Member
Avatar
397 posts
Gallery: 18 photos
Likes: 282
Joined Oct 2017
     
May 30, 2018 15:42 |  #18

My input, please entertain with a grain of salt.

A (proper) flash has varied output of "power". You adjust the power and it fires once at your camer's sync speed (or below).
Easy peasy.


For HSS, the flash does not fire once, it fires in a burst. Even an expensive studio strobe that does HSS will fire in burst.
What happens is the "power" of these sequence of flashes are reduced in order to fire in a strobe and cover the full
sensor with even light.

It is asking a lot of strobe tubes and supporting circuitry to fire FULL POWER in a rapid secession of flashes.
For those that are unknowing, the burst cannot be seen by the naked eye, so it "looks" like one flash...
except to the camera's sensor.

Therefore, given the nature of HSS, you cannot achieve max power output.

Using HSS, you adjust your shutter speed limit the amount of ambient light. This allows you to darken the exposure
of the subject and the background, then using flash you highlight the subject.

As we know from Photography 101, when shooting flash, either by x-sync or HSS, ambient light is controlled
by shutter speed and flash intensity is controlled by aperture.

For someone (like I was a few months ago!) that does not have HSS capabilities (both a camera that supports
it, and a flash that will go into HSS mode), similar effect can be achieved with an ND filter.

Using an ND filter, set the camera's shutter speed to x-sync and adjust the aperture to the desired F number
for bokah, etc. Select the ND or adjust the VND (my pet) to the desired overall exposure that you are going
for, typically a darker background with a flash illuminated subject.

The final step is to adjust flash "power" until the subject is illuminated with the desired effect.

Below, please see three images that I shot prior to having HSS, utilizing X-Sync and a VND.

IMAGE: https://farm5.staticflickr.com/4607/28045659279_d8409e6d6b_c.jpg

IMAGE: https://farm5.staticflickr.com/4619/39114761774_d0115f4576_c.jpg

IMAGE: https://farm5.staticflickr.com/4678/28045393489_0190e6a060_c.jpg

As you can see, the results are very pleasing (IMHO).


However, when you try to use the same system indoors, limited ambient light creates a problem
with you AF system, as I quickly found out, with much frustration. I finally got some of the shots
I wanted, but the process was not joyful.

IMAGE: https://farm5.staticflickr.com/4764/26481094318_96d1971609_c.jpg

In this, and other similar shots, AF had to struggle though the VERY dark VND.


When using an ND filter, it is noteworthy that you are killing both ambient and flash illumination!

There fore, you must increase flash "power" to compensate.

In the end, regardless of the method you use.. you will never recognize full flash power!


ND filter
Pros:
Cheap
Fairly easy
Predictable with practice
Cons:
Limited flash power
AF struggles with indoor light

HSS
Pros:
"Easier" to achieve desired effect
"Faster" to get the exposure you want
IMHO easier to predict exposure settings
AF is not inhibited by reduced light though the lens
Cons:
Camera must support it
Flash must support it
More expensive


In the end, experiment with both.. But from my experience, I am so glad Ive upgraded to HSS!

This may be very elementary for most here, and it may be riddled with technical errors, however
I am confident the spirit of the message is concrete. I encourage corrections where applicable.

If I only helped 1 person with this post, my duty has been done.

Regards,
Andrew

Only shooting one camera; Nikon Z50

  
  LOG IN TO REPLY
nixland
Senior Member
537 posts
Gallery: 3 photos
Likes: 199
Joined Apr 2009
     
Jun 01, 2018 06:42 |  #19

Van Gogh wrote in post #18635896 (external link)
Speaking of physics, this is what I think.
I just imagined this in my head, so not sure it is true or not.

As per my "physics imagination", using higher shutter speeds all else being equal will result in 2 things.
1) Ambient exposure will obviously decrease as higher shutter speed, but to offset it you just use higher ISO or wider aperture opening.

2) Flash power will decrease as you use higher shutter speed if you keep ISO/Aperture the same. Why? Because when shutter speed is higher in HSS, the shutter curtain that moves over the sensor has even a smaller opening. The result is that each portion of sensor is exposed for a shorter period of time to the constant source of light. In HSS flash is not a burst of light anymore, it is more like a constant light source, just like the ambient light. So, when in HSS, the faster the shutter speed the weaker the flash total output. (In fact a more correct description would be the sensor catches less of the flash light, in fact flash power stays the same in HSS over the whole range of shutter speeds, its only because shutter moves faster with faster shutter speeds camera sees less of flash light).

3) No, but what really matters at the end of the day is flash power vs ambient power correlation when we use flash outside. Yes, when using higher shutter speed the camera sees less of flash light output, but with higher shutter speed camera also sees less of ambient output too. Bottom line emans that as you move higher and higher in shutter speed in HSS, camera sees less of both ambient as well as flash exposure. So, perceived power contribution of flash vs ambient stays the same.

4) Bottom line is flash power doesn't decrease when compared to ambient power when moving higher and higher in shutter speed when in HSS mode. Hence, there is no need to use an ND filter to stay at the lower end of shutter speeds in HSS mode.

5) The question comes down too weather one should use a strong ND filter to stay out of HSS mode altogether, but this is another question I will think of next.

Now, is my logic correct or am I on wrong path?

1-3 are correct.

4. In hss mode, we only need ND filter if even at 1/8000 or max shutter speed + lowest ISO, the exposure is still too bright, for example if we use super wide aperture like f/1.2 on bright day light.




  
  LOG IN TO REPLY
ShutterKlick
Senior Member
Avatar
397 posts
Gallery: 18 photos
Likes: 282
Joined Oct 2017
     
Jun 01, 2018 14:05 |  #20

nixland wrote in post #18637051 (external link)
4. In hss mode, we only need ND filter if even at 1/8000 or max shutter speed + lowest ISO, the exposure is still too bright, for example if we use super wide aperture like f/1.2 on bright day light.

True! Even 1.4 or 2.8, sometimes there is just TOO much light even at max shutter speed! Even with my D7500, I keep my ND filters in my camera bag.

Andrew


Only shooting one camera; Nikon Z50

  
  LOG IN TO REPLY
MrScott
Member
243 posts
Likes: 2
Joined Apr 2006
Post edited over 2 years ago by MrScott.
     
Jun 03, 2018 17:32 as a reply to  @ post 18634682 |  #21

Sorry for the late reply. Not saying LV would focus better, but it would boost the perceived brightness. Focus speed, composition and viewing angles with a non-adjustable display are additional items to consider. The 5D3 does have a face recognition mode IIRC for live view.




  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)

3,727 views & 7 likes for this thread
6 stop ND filter - focusing issues
FORUMS General Gear Talk Flash and Studio Lighting 
AAA
x 1600
y 1600

Jump to forum...   •  Rules   •  Index   •  New posts   •  RTAT   •  'Best of'   •  Gallery   •  Gear   •  Reviews   •  Member list   •  Polls   •  Image rules   •  Search   •  Password reset

Not a member yet?
Register to forums
Registered members may log in to forums and access all the features: full search, image upload, follow forums, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, all settings, view hosted photos, own reviews, see more and do more... and all is free. Don't be a stranger - register now and start posting!


COOKIES DISCLAIMER: This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and to our privacy policy.
Privacy policy and cookie usage info.


POWERED BY AMASS forum software 2.1forum software
version 2.1 /
code and design
by Pekka Saarinen ©
for photography-on-the.net

Latest registered member is kubo456
911 guests, 267 members online
Simultaneous users record so far is 15144, that happened on Nov 22, 2018

Photography-on-the.net Digital Photography Forums is the website for photographers and all who love great photos, camera and post processing techniques, gear talk, discussion and sharing. Professionals, hobbyists, newbies and those who don't even own a camera -- all are welcome regardless of skill, favourite brand, gear, gender or age. Registering and usage is free.