Different diffusers
/forum/topic/832461/1

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n0b0
Registered: Sep 22, 2008
Total Posts: 4992
Country: Australia

Dalantech wrote:
I did use the word "possibly" because it really depends on a lot of different factors, flash power being one of them.

I wouldn't discount how much flash duration can impact the detail in a photo though -every full stop change in flash power means that your virtual shutter speed is getting cut in half or doubling depending on how the power level shifts. I'm convinced that what a lot of people blame diffraction for is nothing but "macro motion blur" -movement by as little as half a pixel during the firing of the flash...


What if I already expose for the ambient light like in my hopper sample above and this spider below. 1/50s exposure at midday.



This image is copyrighted by the owner




Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

n0b0 wrote:
What if I already expose for the ambient light like in my hopper sample above and this spider below. 1/50s exposure at midday.


Then you're relying on the shutter speed to freeze the motion in the scene -unless the subject is back lit if the flash doesn't fire the resulting image won't be completely black...

You're starting to argue apples and oranges n0b0...



n0b0
Registered: Sep 22, 2008
Total Posts: 4992
Country: Australia

Dalantech wrote:
Then you're relying on the shutter speed to freeze the motion in the scene -unless the subject is back lit if the flash doesn't fire the resulting image won't be completely black...

You're starting to argue apples and oranges n0b0...


How's 1/50s gonna freeze the motion?

No... I'm trying to say that that flash duration has very little impact, if any, on the detail in a photo because if we follow your logic, any shots with slow shutter speed like mine or even slower for natural light macro would've been soft due to that "macro motion blur" as you call it, don't you think so?



Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

n0b0 wrote:
How's 1/50s gonna freeze the motion?


Simple: Either you or the subject didn't move, or there was very little natural light hitting the subject so that the main source of light was the flash...

n0b0 wrote:
No... I'm trying to say that that flash duration has very little impact, if any, on the detail in a photo because if we follow your logic, any shots with slow shutter speed like mine or even slower for natural light macro would've been soft due to that "macro motion blur" as you call it, don't you think so?


See above -it's possible that the flash was the only light source on the subject. One way to tell is to take two images, one with the flash and one without. If the subject is a silhouette then the flash is freezing the motion for you. The closer you get to the ambient exposure for the subject the more you're relying on the shutter. The further away you get from the ambient exposure for the subject the more you're relying on the flash to freeze motion.

It's very common for me to be out shooting on a brutally sunny day at 2x, F13, ISO 100, and 1/250 and if the flash doesn't fire there's still quite a bit of detail showing up in a scene. Most of the time it's the background and not the subject, and since it's out of focus motion blur won't make any difference.



n0b0
Registered: Sep 22, 2008
Total Posts: 4992
Country: Australia

Dalantech wrote:
n0b0 wrote:
How's 1/50s gonna freeze the motion?


Simple: Either you or the subject didn't move, or there was very little natural light hitting the subject so that the main source of light was the flash...

Sure the subject and I didn't move but what about that half a pixel "macro motion blur" you mentioned? Don't you think it would've affected my photos?



Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

n0b0 wrote:
Sure the subject and I didn't move but what about that half a pixel "macro motion blur" you mentioned? Don't you think it would've affected my photos?


If the flash is freezing the motion -no. Normally it's a problem at higher magnifications than the images that you've posted. Above life size, in the 2x to 5x range, macro motion blur is more of a problem. The reason why I can get away with F13 up to 3x, and F10 (or F11) up to 5x is because I go out of my way to control the motion in the scene. Sure you'll see diffraction if you're looking at 100% crops, or shooting a subject that has some super fine detail, but any loss of detail in an image resized for the web (or in a poster sized print) is going to be due more to motion blur than to diffraction.

This is an old issue n0b0 -one that you'll never be able to sway me on because my experience, and my images, have proved me right. My gallery, and the settings I use on the camera, are my proof...



TheBat
Registered: Oct 14, 2009
Total Posts: 490
Country: Australia

Dalantech wrote:
. The reason why I can get away with F13 up to 3x, and F10 (or F11) up to 5x is because I go out of my way to control the motion in the scene. Sure you'll see diffraction if you're looking at 100% crops,


Hi Dalantech,
Sorry but I'm getting a little confused with these two statements
Firstly, and I'm admitting my 'newbie' tag openly, how do you "Go out of your way to control the motion in a scene", when you have previously stated that you don't use a tripod and hand hold for your exposures?
And secondly, didn't you just state that you didn't believe in diffraction that in your mind it was "macro motion blur" ??
Again guys, I'm new and just trying to get an early grip on an aparently 'testy' subject. Thanks for your input.
Bruce



Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

TheBat wrote:
Hi Dalantech,
Sorry but I'm getting a little confused with these two statements
Firstly, and I'm admitting my 'newbie' tag openly, how do you "Go out of your way to control the motion in a scene", when you have previously stated that you don't use a tripod and hand hold for your exposures?


Left Hand Brace Technique. I also look for things that I can brace the camera on. I placed this dragonfly on a stone wall (it was early in the day and the critter was covered in dew) and I braced the camera on that same wall.



This image is copyrighted by the owner




TheBat wrote:
And secondly, didn't you just state that you didn't believe in diffraction that in your mind it was "macro motion blur" ??
Bruce


You're putting words in my mouth -seems to happen all too often around here

I said "a lot of what people blame on diffraction is macro motion blur." -I never said that I didn't believe in diffraction...


n0b0
Registered: Sep 22, 2008
Total Posts: 4992
Country: Australia

4x, f/10, 1/80s FEC +1, handheld. Again, shouldn't the longer flash duration affected this image with this half a pixel "macro motion blur" thingee?



This image is copyrighted by the owner




I go out of my way to control the motion in the scene.

Please, enlighten me.


Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

n0b0 wrote:
4x, f/10, 1/80s FEC +1, handheld. Again, shouldn't the longer flash duration affected this image with this half a pixel "macro motion blur" thingee?


What longer flash duration? As compared to what? Sorry n0b0, but I've pretty much written you off...

n0b0 wrote:
I go out of my way to control the motion in the scene.

Please, enlighten me.


See the post above yours...



n0b0
Registered: Sep 22, 2008
Total Posts: 4992
Country: Australia

You said,

Dalantech wrote:
The disadvantage is that the flash duration will increase to compensate for the increase in distance to the subject, possibly impacting your ability to freeze motion...


Well I had to place the flash further away from the spider and I also had to increase the FEC, doesn't that make the flash duration longer according to you?

You also said,
Dalantech wrote:
Normally it's a problem at higher magnifications than the images that you've posted.


So I posted a higher mag sample.



TheBat
Registered: Oct 14, 2009
Total Posts: 490
Country: Australia

Dalantech wrote:
. I'm convinced that what a lot of people blame diffraction for is nothing but "macro motion blur" -movement by as little as half a pixel during the firing of the flash...


I stand corrected, but I wasn't trying to put words in your mouth. . . .seems to me that you already have plenty?
You're convinced that it's not diffraction but in fact your self titled "macro motion blur"?
I have re-entered this "macro motion blur" into Google and the only reference that I can find for it is from you. Seeing as though you are single handedly re-writing the photographic hand book- macro edition, could you take the time to explain your wisdom? As I stated, I was asking a simple question as a 'newbie' yet you seem to be quite content to jump down anyone's throat when they dare question you
I won't bother again. . . .
Bruce



Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

Sorry TheBat, but I'm not trying to jump down anyone's throat. Due to the nature of your reply to me I won't be answering you -seems that you've got a very negative opinion of me and no matter what I say it's going to be taken wrong...

I was honestly trying to help you...



M Vers
Registered: Jan 01, 2008
Total Posts: 10333
Country: United States

TheBat wrote:
Dalantech wrote:
. I'm convinced that what a lot of people blame diffraction for is nothing but "macro motion blur" -movement by as little as half a pixel during the firing of the flash...


I stand corrected, but I wasn't trying to put words in your mouth. . . .seems to me that you already have plenty?
You're convinced that it's not diffraction but in fact your self titled "macro motion blur"?
I have re-entered this "macro motion blur" into Google and the only reference that I can find for it is from you. Seeing as though you are single handedly re-writing the photographic hand book- macro edition, could you take the time to explain your wisdom? As I stated, I was asking a simple question as a 'newbie' yet you seem to be quite content to jump down anyone's throat when they dare question you
I won't bother again. . . .
Bruce


I hate to get in the middle of this but feel compelled to sort out any misconceptions you may have in reference to Dalantech's posts. The fact is both diffraction AND motion blur can and do play roles in macro photography. Just how much and or when each of these factors play a defining role varies from situation to situation. John (Dalantech) has had a lot of experience shooting macro and fiddling with flash diffusion and while I'm not recommending you take his word as gospel I will recommend you respect it. It seems he has been touchy lately (sorry, John--it's true ) but try not to take it as an insult for he's usually not--in all actuality he is one of the most insightful and helpful members here in the macro forum.



Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

M Vers wrote:
... It seems he has been touchy lately (sorry, John--it's true ) but try not to take it as an insult for he's usually not--in all actuality he is one of the most insightful and helpful members here in the macro forum.


I'm just a crotchety old fart

Seriously I didn't think I was being touchy, but some of my posts were a little "blunt".



M Vers
Registered: Jan 01, 2008
Total Posts: 10333
Country: United States

Dalantech wrote:
Seriously I didn't think I was being touchy, but some of my posts were a little "blunt".


Well I've certainly noticed it, in fact from a recent thread (remember? ) Regardless words and statements written or typed are too easily taken out of context on these fora. Just easier to avoid translation issues all together.



Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

I remember all too well... doh! I even used a and it didn't help...



Zichar
Registered: May 13, 2009
Total Posts: 1860
Country: Singapore

Well it's an interesting read for me; I think macro shooting is possibly the most unique of all my shooting experiences where I've found myself dreaming and crafting various DIY solutions to perfect lighting - went through this 'check out all transparent/white material and surfaces to find if they make good diffusers' phase which was rather disturbing to the wife.

I'm currently subscribed to the 'get light as close as possible to subject' with a diffuser that's slightly curved away from the hot strong center of the flash (with inspiration from John's puffers and morfa's cross-in-the-middle-of-the-icecream-box diffuser over at Juza).

What I have currently is a flat 2x6 piece of architectural model styrene with velcro at the ends (moved from building the complex ones to the simplest possibly because of transportability and ease of attachment). This wraps around the front of my SB-R200s to create the curved surface.

But here's my conundrum:
I've read from John's posts and blog, seen the numerous DIY stuff and also the commercial products such as the aforementioned softboxes, to know I should keep the diffuser enclosed and with sufficient reflective material to not lose flash power (instead focusing it through the diffusing material).
Yet, if I'm already close enough, that shouldn't matter? And even so, the light 'escaping' is still in the same direction and should be sufficiently diffused away form the source.
Also, at that distance, and with dialled down FEC, it's already very strong, wouldn't the above just make it even stronger?

*Sorry to partially hijack your thread, TheBat, but all this talk about diffusers have rather seized me at this moment...



Dalantech
Registered: Jan 31, 2005
Total Posts: 12308
Country: Italy

Zichar wrote:
But here's my conundrum:
I've read from John's posts and blog, seen the numerous DIY stuff and also the commercial products such as the aforementioned softboxes, to know I should keep the diffuser enclosed and with sufficient reflective material to not lose flash power (instead focusing it through the diffusing material).
Yet, if I'm already close enough, that shouldn't matter? And even so, the light 'escaping' is still in the same direction and should be sufficiently diffused away form the source.
Also, at that distance, and with dialled down FEC, it's already very strong, wouldn't the above just make it even stronger?


Maybe we should start a diffusion thread to share ideas.

I've built my current diffuser both with and without the reflective material. With it the light looks more diffused, and with the flash set to E-TTL the amount of flash power that I need to get a proper exposure is less. I think that the increase in diffusion is due to the light hitting the matte surface of the reflector, scattering, and then coming out the front of the diffuser. I've also had the impression that flash duration can effect the perceived diffusion level of the light -the lower the flash duration the less harsh the specular highlights look and therefore the light looks more diffused. I could be wrong on that last point -but it seems to fit what I have observed (and recently a friend of mine who's a photographer mentioned the same effect even though he'd never heard me talk about it).



TheBat
Registered: Oct 14, 2009
Total Posts: 490
Country: Australia

Zichar wrote:
*Sorry to partially hijack your thread, TheBat, but all this talk about diffusers have rather seized me at this moment...


Hi Zichar,
No apologies necessary, it's an open thread from a genuine question. All questions, reasonings/opinions are welcome.
Seems to be just one 'pig-headed' gentleman who seems to be an opinionated 'phrophet' on the subject, that's all
What is it that they say about genius' ?
Bruce



Tom Hicks
Registered: Feb 16, 2003
Total Posts: 22937
Country: United States

Please, lets all go for a walk and come back later., we all do things differently , no right no wrong . John is passionate about macro and that is good , passion is what it take to get the most out of your own success as well as feed others and creating excitement. It was my passion for Macro that got this forum started . But we all need to take a breath. In the end we will all succeed in our art if we just put our focus in the right spot. I for the most part have stopped teaching here , but instead just try to provoke thought , and then ya'll can come to your on conclusions.

Tom ,



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