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-   -   Flash Diffusion (https://www.worldphotographyforum.com/showthread.php?t=1852)

Don Hoey 18-12-05 22:47

Flash diffusion
 
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Quote:

Raw flash should be considered as a bright pin point of light. You can liken it to the sun on a bright day, as that is also a very bright point source of light that gives harsh shadows. When partialy obscured by cloud it is not so bright and any shadows are far softer. Totally overcast gives no shadows as there is no longer a key light, and light on a subject is coming from all around.
The key to a soft flash is diffusion. A way of making the point source bigger. Just as in the examples of sunlight the more diffuse the flash the softer the light. You will however loose a bit of the flash units power. If the unit is a TTL one exposure will be automatic and of no concern.

Diffusing a flash can be done in a number of ways. If it is a seperate flashgun then diffusing attatchments such as the one shown in the attatched picture can be used. These are very effective for their size which is why you will see them being used by the press. The flash can be bounced of a larger surface to increase the size of the light, or fired though a white material from a short distance to achieve the same. Unfortunatly on compact cameras the proximity of the flash to the lens limits options to a bit of tissue held over the flash tube ( fingers out of the way of the flash ).

As the options are so large I attatch a link to the Warehouse Express site where there is a large range on show. When the diectory on the left side loads go to Photographic - Flashguns - Lumiquest and Stofen. http://www.warehouseexpress.com/index.cfm

Attatched picture shows Stofen type diffuser.

Don Hoey 20-12-05 13:30

Flash diffusion 2
 
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Posting this now as it may help Stephen as he is looking at possibly venturing into portrait photography.

To save scrolling back through past posts a reminder........

Quote:

Raw flash should be considered as a bright pin point of light. You can liken it to the sun on a bright day, as that is also a very bright point source of light that gives harsh shadows. When partialy obscured by cloud it is not so bright and any shadows are far softer. Totally overcast gives no shadows as there is no longer a key light, and light on a subject is coming from all around. All of this can be achieved with flash.
The primary consideration is trying to convert a point source of light into a far bigger light to simulate the above.

I am attatching another graphic to hopefully explain the affect on shadows.

The lower reference to studio flash and brollie is that this is something most will have seen and can relate to.
Studio flash units are used professionally as they have a number of advantages over small flash guns. ..... More power.......variable output...... faster recycling times.......modeling light facility to name a few things. Although a portable flash can be used with a brollie but because of lack of power the flash to subject distance is very limited. The downside of studio flash is that the camera cannot control exposure and it has to be done manually.

I found some good stuff by Steve Aves on the Warehouse Express site. A good read if you are interested.
Click the link and go - Photographic - Studio Lighting -
Lighting Glossary - Steve Aves article :)
Lighting Guides - Steve Aves article :)
Product Reviews - Steve Aves article :)
Bowens
Elinchrom
Interfit
Interfit Pro
Interfit Stellar
Lastolite

http://www.warehouseexpress.com/index.cfm

My graphic attatched

Don

Don Hoey 24-12-05 23:16

Diffusion 3
 
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I am going to post a series of pics to graphically show the effects as a continuation of Diffusion 2. Due to the limits of uploading pics this will be spread over several posts.

I am using this to post a picture of flash units to give some idea of the relative sizes of the square area from which the light starts its journey.

This is important in that large subjects will require light coming from a source of greater area, in order to diffuse shadows to the same extent, as a smaller subject and smaller light.

I will post a set of 4 to show effect tomorrow.

Don

Don Hoey 25-12-05 15:26

Diffusion 4
 
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Attatched are images that show the effect of flash.

Notice how the shadows start hard on direct flash though to soft on diffused.

The pictures were taken in overcast conditions in my lean to. This was to show the effect on shadows to the best without too much influence from natural sunlight.

Flash exposure was TTL to not introduce any complications at this stage.

In the behind the scenes image you can see the set up. This type of photography is often referred to as Table Top photography. Ideal for any still life.

If you only have a compact camera you can still do Table Top using a 'slave' and remote flash. The power of the remote flash can be controlled by moving it closer to, or further away, or adding sheets of kithen toweling over the flash as this absorbs light.

Any number of flash units can be used, but balancing the light becomes more complicated the more units you use.

Don

Canis Vulpes 08-01-06 16:29

Quote:

Originally Posted by Don Hoey
Thanks for that. It was the Omni Bounce bit that confused me, I refer to them as Stofen as this was when it came out their only product, and a killer one at that. I use one all the time. The best addition to your flash you can get, and only £15:95 from Warehouse Express.
Pic from post #4. http://www.worldphotographyforum.com...0&d=1134942009.

Don

I have been looking for local stofen supplier when I found this comparison between two Stofen, Lumiquest and direct flash.

http://www.toddwalker.net/e20/flashtest/

Don Hoey 08-01-06 18:32

Quote:

Originally Posted by Stephen Fox
I have been looking for local stofen supplier when I found this comparison between two Stofen, Lumiquest and direct flash.

http://www.toddwalker.net/e20/flashtest/

Handy link Stephen,

It does show how hard direct flash is.

My first system flash was the Vivitar 283 and I had a 45deg bracket that held a large card and gave a slightly softer light than ' Lumiquest, white insert, no diffuser '. Once I got my hands on a Stofen I gave up using this.

There used to be a flash head described as being ' bare bulb ' in which the whole tube was above the flash body and had no reflector. When triggered the light emitted went everywhere. A bit like a lightbulb with no shade. Great for interiors as light bounced everywhere so any shadows were soft. For me the Stofen is the nearest to that.

In this test the ' Lumiquest, no insert, no diffuser ' does well as some light comes from the Lumiquest and some from the ceiling so making the light source really diffused. Very similar to ' Stofen Omnibounce, 90 degree bounce '

So are you still going with Stofen ? I presume its for your SB600. Two guns both with these ....... that will be light everywhere. :cool:

Don

Canis Vulpes 21-10-06 13:39

Shoot through verses reflective brolly technique
 
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I spoilt myself yesterday and splashed out on a light stand and brolly. I am no expert in the field of brollies but this one allowed dual use and came recommended. A white inner allows shoot through when the outer reflective element is removed. I decided to test both ways what follows below are my findings.

Traditional Brolly (images 1&2)

Two flashes attached to a light stand and fired using remote camera cord. Light is bounced around the brolly and comes out diffused in all directions. Lots of light is lost and both flashes ate set to i-TTL +1 EV. Shadow is fairly heavy with two shadows near the tail most likely one from each flash. Colours and contrast are rich and good. Reflectors used in to bring some light back and soften shadows more. This method was fairy difficult to get close to the subject.


Shoot through (images 3&4)

Two flashes attached to light stand fired by the camera using a remote flash cord. Much light is lost as it spreads out from the curved diffuser. Due to the way light is spreading out it is possible to use other reflectors to bring some back and illuminate other parts of the subject. This method is less directional and more diffused creating softer shadow. Contrast seems slightly flat compared with images 1&2. Upper wing surface seems better light due to large lastolite reflector claiming wasted light back. Shoot through was easier to get close to the subject.

Conclusion
These two lighting techniques allow good diffused lighting with fairly soft shadows no harsh highlights. Colours and contrast are better using traditional method but shoot through creates softer shadows and more even lighting also permits use of other reflectors to illuminate parts of the subject that may be in shadow. It is difficult to get a brolly over a subject like the test whereas shot through was much easier.

Don Hoey 21-10-06 21:39

I can see we are looking forward towards the darker days Stephen.
Guess when you are on bread and water you can easily use the dining room as a studio.:)

Brollie used as in image 3 provides an economical softbox. I see you managed f20 at ISO 200 which is quite impressive.

If you see a decent s/h flash around guide no 45 or more, that can be remotely triggered at full bore, you can recover your SB800 for fill in.

For future reference it would be nice to see a pic of the flash mounting in use on the stand.

Don

Canis Vulpes 22-10-06 14:05

5 Attachment(s)
Quote:

Originally Posted by Don Hoey (Post 12574)
For future reference it would be nice to see a pic of the flash mounting in use on the stand.

The stand is terminated in a 3/8" thread (pic1) and the brolly/hot shoe adapter slides over and screws in to form a compression (pic2) by rotating the bottom tightener. A brolley is attached in a similar way by inserting through the hole at the top of pic2. Angle adjustment is made by the joint and released by the middle tightener. Pic 3 shows assembled with hot shoe flash foot. Flash shown assembled in pic 4 diffuser optional but I found provided softer light in both applications above. Additional flashes can be attached using the adapter in pic 5 when brolley shaft is placed through the hole and tightened. This is not perfect as the hole is too wide but it was packed with card to make in effect brolley shaft wider in diameter. SB-800 on remote cable was attached to adapter in pic 5 as has a 1/4" suitable for remote cord.

Lello 28-10-06 15:35

For those of you still following this tread with interest, A free white reflector comes with the November issue of What digital Camera. I've just got mine (pretty nifty)

Canis Vulpes 30-10-06 15:09

Quote:

Originally Posted by Lello (Post 12672)
For those of you still following this tread with interest, A free white reflector comes with the November issue of What digital Camera. I've just got mine (pretty nifty)

Thanks for the heads-up on that Lello. Those reflector/diffusers are great for beginners who have an appetite for experimenting and learning flash photography. If you look back through this thread I started using kitchen roll around flashes then to these free small reflector/diffusers, I invested in a large lastolite reflector/diffuser and now I have a brolly. These free ones allow experimentation at little cost - there superb!

Don Hoey 30-10-06 22:38

Quote:

Originally Posted by Lello (Post 12672)
For those of you still following this tread with interest, A free white reflector comes with the November issue of What digital Camera. I've just got mine (pretty nifty)

Thanks for that Lello.

I can never have enough reflectors. :)

Don

Canis Vulpes 26-11-06 15:19

3 Attachment(s)
Quote:

Originally Posted by Don Hoey (Post 13637)
Foxy's kit is not very technical. Having seen the brollie, it is a 2 in 1 job. It is just that Foxy is using it in a novel way. Perhaps he will post an explanation of it.

Don

Okay... the not so technical brolly is a two in one that allows traditional use or shoot through. The brolly is white but an outer silver reflector permits normal use and removed for shoot through. During my visit to Don two weeks ago we used a second brolly to catch and direct escaping light behind the white shoot through to use every bit of the power of my SB-800 unit. Last week it dawned on me that the reflector part could be put in effect backwards to perform similar to a softbox.

Pic 1 - Traditional reflect back
Pic 2 - Shoot through
Pic 3 - Softbox!

It pointing down is an issue but it can be tilted 30 degrees or so.

Brolly is a Bowens 36" Silver / White (BW4036), cost £25-30.

Don Hoey 26-11-06 17:51

1 Attachment(s)
Quote:

Originally Posted by Stephen Fox (Post 13803)
Pointing it down is an issue but it can be tilted 30 degrees or so.

Stephen,

Excuse cribbing a crop of an ealier shot of your kit.

You may have thought this redundant now you have your other bits. Ideal clamp to stop reflector part slipping forward.

Attatch to brolley spike before putting the reflector part on. A bit of guess work for position. I doubt the reflector would slide over it.

Don

Lello 09-12-06 18:00

I made mine today, Works a lot better than it looks!!!!!:)
look at this link, And watch the video (good for a laugh)
http://www.abetterbouncecard.com/

Jon Sharp 09-12-06 18:30

He should have been on Blue Peter!

Canis Vulpes 09-12-06 19:16

Quote:

Originally Posted by Lello (Post 14347)
I made mine today, Works a lot better than it looks!!!!!:)
look at this link, And watch the video (good for a laugh)
http://www.abetterbouncecard.com/

Great find Lello. I'll be making one as soon as I can find some photo paper.

Anyone know what he is on about with that foam paper from 'Rags' ? :confused:

Lello 09-12-06 19:46

All I need now is a black garter to attach to the flash:)

Saphire 09-12-06 20:12

Thanks Lello that was brilliant. I made something similar a while ago out of a white paraffin bottle, I never thought of putting it at the angles he was showing I normaly just have it going straight up.
The foam card I think we can get from craft shops, I will have to get a sheet and give it a go.

Saphire 09-12-06 20:13

Quote:

Originally Posted by Stephen Fox (Post 14349)
Anyone know what he is on about with that foam paper from 'Rags' ? :confused:

Stephen. I think it is the same stuff you can get at most craft shops, they do it in loads of colours.

Don Hoey 09-12-06 21:44

Great link Lello. Something easy to make for about £1:50 for a couple if you go for the foam version.

I bought some of this in black that I cut and glued to the top section of my tripod legs. Keeps your hands warm when using tripod outdoors in cold weather. 2mm thick and its called Darico FOAMIES. As Christine says it comes in loads of colours from a craft shop.

Don

mcliu 22-03-07 20:37

Wow, I have learned quite a lot today, got so many links(interesting ).Thanks to Don Hoey ,Stephen Fox & of course lello.Deep inside I know I have to keep coming back to learn more.This is my "referance point" .BTW, Lello finally I succeeded in making " Home made ring flash".God I was so excited that I just could not believe my own eye when I saw the images.To be true to you,I used Jonney walker(Black label) bottle placed on the golden reflecting surface with "tabletop globe" as a touch for class. Light was evenly spreaded.Reflections were well contolled ( I think that is the hardest test one can put you into).Infact the texture too have come to very commandable level.I use to do lot of "photoshop work" to rectify my images.But after this I am convert.Infact my local kodak outlet personel also shocked to know that my "that image has no PS work ".I think you are going to get "more follower" in near future.Now at the same breath let me thank to all the members of this forum for all the pains and labours you all are going through will not go wasted.It will be remembered through the excellent and the brillient pictures that will be produced through the knowdage you provide.That is the 'ovation" for you all.Thank you all once again

Lello 22-03-07 21:48

Hi Mcliu
I'm glad to hear that you are leaning and enjoying it here on WPF. I'm going on holiday for two weeks, and when get back I expect see some shots taken with your ring flash.
Regards
Lello

Don Hoey 22-03-07 22:31

Hi Mcliu,

Nice to hear you are having a bit of fun with your flash. :)

Don

Gidders 24-03-08 16:23

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As some of you will know when I'm not taking photographs I go dancing modern jive - see me on youtube. Well last night I went to a new venue opening. I'd said to the organisers that I would take my camera and take a few snaps for their website/facebook etc. rather than use the on camera flash, I took my Metz CT45-4 along with the idea that I could bounce off the ceiling and use the forward facing inbuilt slave for infill. I thought the results I got were a bit disappointing. Fortunately I was shooting in RAW and these have had fairly heavy doses of "fill light" applied in Lightroom but the shadows, particularly in the background, are still much harsher than I would have liked.

I think the problem was that the ceiling was quite a high dome so I wasn't getting much bounce, and too much in fill from the slave (the power of which is not adjustable) I did try a few shots with the slave off but these just tended to be a bit under exposed. I've had this problem before as ceilings in dance halls tend to be high.

This got me thinking about diffuser attachments, and reading the threads here the Stofen seems to get a lot of mentions. I'm just not sure how much benefit that it would give in the sort of rooms that I will be shooting in without much ceiling bounce factor. The alternative would appear to be something from the Lumiquest range but their products don't seem to have as much a following.

The comparison that Foxy posted
Quote:

Originally Posted by Canis Vulpes (Post 2268)
I have been looking for local stofen supplier when I found this comparison between two Stofen, Lumiquest and direct flash.

http://www.toddwalker.net/e20/flashtest/

is quite instructive but he is working a a room with a low ceiling so not that comparable to my situation.

I've had a go at mocking up something like the Lumiquest midi bouncer and will post pics and results in the next post but has anyone any thoughts on which way I should go?

Gidders 24-03-08 16:33

4 Attachment(s)
Following on from my post above, I used some textured old english white mount card to make something like the Lumiquest midi bouncer.

The reflector is 8" along the top edge, 5" along the back edge and ~4.5" deep. Tests showed that I was loosing ~ 2 stops compared to direct flash, but leaving the Metz on Auto and it seems to get the exposure about right. I did have to adjust the white balance from the flash setting of 5900K to 5200K - I guess because my card is not true white.

yelvertoft 24-03-08 18:02

Clive,

Firtly, I'd like to congratulate you on your dancing. The pair of you in the shopping mall are clearly having a lot of fun, it shows in spades. Not a bad pair of movers either.

On the matter of diffuser's, if you're bouncing off the ceiling I don't think it will make a lot of difference, except losing you power, if you use a diffuser. The home made Lumiquest seems to be doing a good job and as long as your gun has the ooomph to cope with it then I think you'll get better results than trying to bounce from an unfeasibly high ceiling.

In the 2nd picture you've attached, the bloke in the orange shirt and his partner have a great poise.

Gidders 27-03-08 21:14

2 Attachment(s)
Quote:

Originally Posted by yelvertoft (Post 27836)
Clive,

Firtly, I'd like to congratulate you on your dancing. The pair of you in the shopping mall are clearly having a lot of fun, it shows in spades. Not a bad pair of movers either.

Thanks Duncan - that was taken ~ two years ago so hopefully an even better mover now ;)

Had a go with my improvised Lumiquest on Tuesday evening. While its still obviously flash photography, and the shots are record shorts not works of art, I think the results are better

yelvertoft 31-03-08 13:09

Clive,

Just been reading elsewhere about another technique to reduce the harsh flash issues you found on your first attempt. The suggestion was to set the camera to manual mode and adjust the settings to give -1 stop exposure under the ambient lighting conditions, bumping up the ISO if needed. The general ambient lighting will probably not be changing that much in your hall, so it shouldn't be necessary to tweak it that much during your photo session. Having fixed these settings to give -1 stop underexposed from ambient, fit the flashgun and set it to TTL auto mode and use the flash to provide the additional lighting needed to bring up the 1 stop needed to get the exposure right. The flashgun will need to vary its output depending on camera to subject distance, hence the flash needs to be set to TTL auto. By balancing ambient with flash this way it apparently reduces the harshness of the flash seen on your first images and softens the shadows.

I've had no direct experience of using this technique, but I saw it described as a solution to exactly the kind of issues you're having and thought it may be of use to you or someone else.

Regards,

Duncan

miketoll 31-03-08 20:48

When I had a similar Metz I found the foreward facing flash fill in flash tended to overdo it a bit as well so attached the wide angle adapter supplied with the gun to the secondary flash which helped. An alternative would be to diffuse the fill in tube with the traditional bit of tissue paper.

Gidders 04-04-08 18:19

2 Attachment(s)
Following the tip from Duncan / MattMatic, had another go at dancing on Tuesday night.

Now unfortunately the Metz CT 45 can not be used in TTL mode (the CL 45 'digital' can if you have the right adaptor). However undaunted I metered the ambient light at somewhere between 1/30 to 1/50 at f 5.6 ISO 1600 so I set the camera on manual with that f stop & ISO with the shutter speed set to 1/50. I set the Metz on Auto but next problem was maximum setting for ISO of 1000 so I set this for 800 and f 4 which should give the same light output. In fact I was finding some of the whites a bit blown out particularly if the dancers were close to me so I reduced the f stop to f 2.8 and still used the diffuser that I used previously

I think the shadows are definitely softer than the ones I posted previously (and I still had to add some "fill light" in Lightroom.) Maybe I should have reduced the shutter speed still further to allow even more ambient light.

yelvertoft 04-04-08 18:24

A lot less "cardboard cut-out" effect with these ones. A real improvement.

Contest_Guru 22-05-13 10:51

Thank you Guys
 
Thank you for posting this guys this may help me! I am still a newbie with it comes to photography flash, I always end my photos getting blurred so thanks for sharing this tecchnique ;)


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