Ring flash

[Patrick]

Re: Ring flash

It really is VERY simple... Much like a "Blue Peter" product

No where near enough light output for portraits. The range is about 2ft maximum with optimum lighting within the range of the 35 & 50mm Macro Lenses in Macro mode.

If you want lots of light, to work at a distance, then something like this will do the trick.


But make sure the person knows just how powerful the flash will be.
Even "normal" ring flash can be a bit bright for a lot of people, in much the same way as bare on-camera flash.

Softening the light gives by far the better results.

Agreed softening the light gives better results.

Found a not dissimilar bracket on Amazon

[ame]http://www.amazon.co.uk/Polaroid-Shaped-Bracket-Standard-Mounts/dp/B005FRI2XK/ref=sr_1_1?s=electronics&ie=UTF8&qid=1367510523&sr =1-1&keywords=Polaroid+o+ring[/ame]

Just ordered one for myself.

Patrick

[Ian]

Re: Ring flash

Patrick, you mentioned the inverse square law, but is that really important for macro? The inverse square law explains why there is a sharp drop off in illumination brightness beyond a certain point. But with macro the lights will be very close to the subject, so the threshold point where the brightness falls away dramatically would, I estimate, be further in distance than the macro subject distance. This also explains why macro flash units don't need to be very powerful compared to standard flash units that operate at a longer distance.

On the other hand, macro can demand smaller than usual f-stops in order to increase depth of field. That could bring the light drop-off distance down I guess.

Ian

[devilgas]

Re: Ring flash

i'll try and run some totally unscientific tests on the LED flash unit later this afternoon. certainly, when i tried it a few days ago, the light output was ample for close-up macro work but not sufficient for anything other than close portrait work. not sure if it did TTL feedback or not as, iirc, i had the camera on manual setting. i literally just wanted to check it worked

[Graham_of_Rainham]

Re: Ring flash

This looks "interesting" if only for the somewhat larger size and the many fittings that come with it. The diffuser while it will knock down the power considerably will help with portrait photography.

The specs look good for a LED based unit, but for the price; I expect the quality will be commensurate.

http://www.ebay.co.uk/itm/Aputure-HL-48-Macro-Ring-Flash-Light-for-Olympus-Nikon-Canon-600D-650D-LF174-/140968741234?pt=UK_CamerasPhoto_CameraAccessories_CameraFlashUnits_JN&hash=item20d2644972

[Ian]

Re: Ring flash

i'll try and run some totally unscientific tests on the LED flash unit later this afternoon. certainly, when i tried it a few days ago, the light output was ample for close-up macro work but not sufficient for anything other than close portrait work. not sure if it did TTL feedback or not as, iirc, i had the camera on manual setting. i literally just wanted to check it worked

My smartphone's single white LED is surprisingly powerful, so if a dedicated LED light had, say 16 of the same power LEDs, that would be 4 stops of extra brightness, which is would be quite useful even at moderate distances.

As Patrick did mention, one weakness of LEDs is that as a constant light source there is no benefit in the form of freezing action. This might be useful for certain types of macro work.

Ian

[Ian]

Re: Ring flash

Can I just give our Amazon shop a plug? If you need to order anything from Amazon, please consider using our Amazon shop in order to help us to finance this site. It costs you nothing

Our Amazon shop can be found here:

http://dpnow.com/Shop.html

..or click on the 'shop' button on our site navigation options.

Thanks,

Ian

[Patrick]

Re: Ring flash

Patrick, you mentioned the inverse square law, but is that really important for macro? The inverse square law explains why there is a sharp drop off in illumination brightness beyond a certain point. But with macro the lights will be very close to the subject, so the threshold point where the brightness falls away dramatically would, I estimate, be further in distance than the macro subject distance. This also explains why macro flash units don't need to be very powerful compared to standard flash units that operate at a longer distance.

On the other hand, macro can demand smaller than usual f-stops in order to increase depth of field. That could bring the light drop-off distance down I guess.

Ian

Hi Ian

I may be quoting the wrong law for what I am trying to explain, however the phonemenome is not dissimilar.

Using extension tubes or bellows to increase the distance from lens to film/sensor plane that allows closer focusing results in a fall off of light reaching the sensor, and exposure benifits by being increased for accurate results. If a macro lens is used its not a problem, unless for even closer focusing extension tubs/bellows is used.
I remember well doing the exercise at Wednesbury photo collage way back in 1966 to demonstrate the effect, film of course but principles don't change only technology.
Modern cameras with their sophisticated auto exposure systems automatically adjust for this so it goes largly unnoticed, but if a low level light source is used it could result in longer exposure than is ideal.
I will sometime today check my trusty photo encyclopaedia (dating back to 1966, might be collectors items now) to get the correct law.

Patrick

[Patrick]

Re: Ring flash

Can I just give our Amazon shop a plug? If you need to order anything from Amazon, please consider using our Amazon shop in order to help us to finance this site. It costs you nothing

Our Amazon shop can be found here:

http://dpnow.com/Shop.html

..or click on the 'shop' button on our site navigation options.

Thanks,

Ian

I tried to use it with yesterday's purchase, got as far as "go to checkout" to put my password in and it would not work, had to return to my usual method.

Patrick

[Ian]

Re: Ring flash

I tried to use it with yesterday's purchase, got as far as "go to checkout" to put my password in and it would not work, had to return to my usual method.

Patrick

That's worrying! I will check this...

Ian

[Ian]

Re: Ring flash

Hi Ian

I may be quoting the wrong law for what I am trying to explain, however the phonemenome is not dissimilar.

Using extension tubes or bellows to increase the distance from lens to film/sensor plane that allows closer focusing results in a fall off of light reaching the sensor, and exposure benifits by being increased for accurate results. If a macro lens is used its not a problem, unless for even closer focusing extension tubs/bellows is used.
I remember well doing the exercise at Wednesbury photo collage way back in 1966 to demonstrate the effect, film of course but principles don't change only technology.
Modern cameras with their sophisticated auto exposure systems automatically adjust for this so it goes largly unnoticed, but if a low level light source is used it could result in longer exposure than is ideal.
I will sometime today check my trusty photo encyclopaedia (dating back to 1966, might be collectors items now) to get the correct law.

Patrick

OK - yes, just like with teleconverters if you use an extension tube less of the light that is transmitted by the lens covers the frame so the brightness is reduced. In fact some macro lenses also lose light at very close focus even without extension tubes.

Ian

[Graham_of_Rainham]

Re: Ring flash

That's worrying! I will check this...

Ian

While you are checking, sometimes that link sends me to the US site where everything is annoyingly cheaper being priced in Dollars, reminding me of how we get ripped off in the UK.

Thanks

[devilgas]

Re: Ring flash

as promised.....

ebay £16 special - Aputure Flash HL-48 Macro LED Ring for Nikon Canon Panasonic DSLR Camera


the flash unit






for the test shots below, subject to camera distance is about 20cm.
camera in shutter priority mode and set to underexpose by 1/3 stop.
shutter set to 1/25s.
lens minimum aperture is f/5.6


test shot with flash OFF.
camera chose wide open aperture of f/5.6



test shot with flash set to continuous lighting.
camera chose f/11



test shot with flash set to fire as a strobe (in theory, TTL).
flash triggered, but camera still chose wide open aperture




so, when the unit is set to be brief flash, it doesn't appear to do TTL. to this end, i think that continous is the way to go. it seems to work quite well as macro. need to do more tests to see what it's like when used for people shots. in fairness, it does state MACRO in the product name, so perhaps expecting it to do portraits is unfair. still, i think it could be useful to provide a nice ring catchlight.

[TheBull1875]

Re: Ring flash

This is getting complicated! :-)

[Ian]

Re: Ring flash

For £16 I don't think you can really go wrong with this?

Ian

[TheBull1875]

Re: Ring flash

Kind of what I am thinking ;-) By the way, your liknk takes me to the dollar Amazon as well Ian.