MaticKos Photography
15Mar/140

Speedlight light spread in umbrella test // Flash razprsitev v dezniku

I finally had some time and did some sample images of speedlight diffusion inside a white umbrella with different settings. I never did any testing like this before, I knew from experience what different settings bring you, but it's still interested to see how light behaves with different modifiers. I was mostly interested in the way light spills inside the umbrella, what makes the most even spread. Stofen (or any other brand) dome and internal flash diffuser are quite similar, but I'd say internal flash diffuser is better.

So, nothing to scientific, Nikon SB800 on a stand, manual mode at 1/16 power with a 100cm Elinchrom white umbrella. Nikon D800 in manual mode, ISO200, f16. Triggering was done by PocketWizards Flex units.

First set was done shooting into an umbrella, second from the opposite side, outside of the umbrella.
Sequence was:

1.) SB800, 1/16, no aditional modifier - 24mm
2.) SB800, 1/16, stofen diffuser or dome - 14mm
3.) SB800, 1/16, internal flash diffuser was pulled out - 17mm
4.) SB800, 1/16, internal flash diffuser was pulled out + stofen dome on top - 14mm

After the sample shots, I measured the light output using a Polaris light meter set at ISO800.
The results were:

1.) f5
2.) f4.5
3.) f4.5
4.) ???*

For the #4 sequence, light meter was unable to measure light at one meter. At around 70cm it gave a reading of f4, then was unable to read anything lower then that. I found that very strange and still don't know the reason why the meter couldn't read f2.8, f2, f1.4,... etc.. I tried with a new battery but it didn't help. Tried the same measurement with #3 setup and it gave a normal readings down to f0.5 with more distance used. So, no reading for #4 sadly, but it's clear from the sample shots that the light was very weak, 2-3 stops loss at least.

umbrellatest
Končno sem imel nekaj časa in naredil nekaj vzorčnih fotografij kako se svetloba razprši znotraj oz z uporabo dežnika. Kako se svetloba razprši sem vedel po izkušnjah, vseeno pa je zanimivo dejansko videti kaj povzroči različni modifikator in različni milimetri. Po pregledu fotk lahko vidimo, da stofen in interni difuzer naredita zelo podobno razpršitev, a vseeno je interni difuzer malenkost boljši.

Nič posebaj tehničnega, Nikon SB800 na stojalu, ročni (manual) način z 1/16 moči, 100cm velik Elinchrom bel dežnik. Nikon D800 v ročnem načinu, ISO200, f16. Proženo z Pocket Wizards Flex enotami.

Prvi komplet je bil fotkan v dežnik, drugi pa z nasprotne strani, zunanja stran dežnika.
Vrstni red je bil sledeč:

1.) SB800, 1/16, brez dodatnega modifikatorja - 24mm
2.) SB800, 1/16, stofen difuzer - 14mm
3.) SB800, 1/16, uporabljen je bil interni difuzer - 17mm
4.) SB800, 1/16, uporabljen je bil interni difuzer + stofen difuzer - 14mm

Po izdelavi fotk sem zmeril še izgubo svetlobe z Polaris svetlomerom pri ISO800.
Rezultati so bili:

1.) f5
2.) f4.5
3.) f4.5
4.) ???*

*Pri zadnji meritvi svetlomer nikakor ni želel izmeriti svetlobe. Pri cca 70cm razdalje je podal vrednost f4, nato pod to ni šel, tudi pri par cm dodatne razdalje. Zakaj ni podal vrednosti f2.8, f2, f1.4,.. itd si ne znam razložiti. Tudi z novimi baterijami v svetlomeru napaka ostaja. Podobno meritev je pri postavitvi št. 3 normalno opravil, vse do f0.5 pri večji razdalji merjenja. Tako žal za postavitev št. 4 nimam vrednosti, vseeno pa je že po fotkah videno, da je izguba svetlobe občutna, vsaj 2-3 zaslonke.

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19Aug/131

Zmajcice – Dragon Ladies

Fotkanje plesno navijaške skupine Zmajčice za prihajajoče Evropsko prvenstvo v košarki 2013.
Solo fotke sledijo..

BACKSTAGE: http://on.fb.me/Tvu2Xm

Zmajcice-FULLSET-portrait-blog

3Feb/130

GoPro field of view (fov) and image quality compared

So I have a GoPro Hero2 for a long time now. It's mostly used for backstage or as a "scene" camera since the footage is perfect adequate for my needs and the wide angle is just what I need. The one thing that always left me wondering was it's Field Of View (FOV) settings while using a fixed lens and the image quality associated with it..
In 1080 mode Hero2 has three options: wide (180 degrees), medium (127 degrees) and narrow (90 degrees). There are no interchangeable lens, no moving glass, no optical zoom, so the change in FOV has to be done by software, right? The software just crops into the original 1080 wide shot and enlarges the crop to 1920x1080. So it doesn't make any difference if you record in wide mode, then crop&enlarge if needed later in post. At least that's what most users on forums say, but is it true? Well, I had a few hours to kill while my video was rendering, so I did a quick test.

Three 1080 clips on a tripod: wide, medium and narrow. Done indoor, in poor light to maximize defects and to see the noise reduction done by the GoPro.
All screenshots are unaltered, at 100% view, cropped to center 700x700px for easy(er) handling on blog.

Then I took the wide shot and enlarged it for about 128%, to fit the original medium shot from the cam.
If you use your keyboard left and right arrows, you can quickly switch between the two images and compare them.

There is a slight brightness and color temperature difference, but the sharpness and noise difference is quite obvious. The original medium shot is a lot sharper and clearer then the enlarged wide shot. So I guess GoPro doesn't only crop and enlarge, it does a few other modifications as well.

gopro-widemedium

Here's the same comparison between wide and narrow shot. Wide shot enlarged to fit the original narrow shot.
Don't really have to comment, do I?

gopro-wide2narrow3

 

This noise was bothering me too much, so I went out and did some some more outdoor samples.

Taken on clear sunny day in sunlit area, original medium shot and wide shot enlarged in Photoshop. There's some contrast difference, but that's easily fixed in post, but the sharpness difference is obvious.

gopro-widemedium2

Here the original narrow shot with enlarged wide shot. As before.. no comparison.

gopro-wide2narrow1
Here's another original narrow shot and enlarged wide shot; sunny day, shade:

gopro-widemedium3

and original narrow shot with enlarged wide shot:

gopro-wide2narrow

Last sample set, original medium shot and enlarged wide shot; sunny day, open shade:

gopro-wide2medium

and original narrow show with enlarged wide shot:

gopro-wide2narrow4

 

My conclusion..  It is NOT the same filming in wide mode (then cropping & enlarging in post) or changing fov modes in camera itself. If sharpness is your main priority, it is far better to pick your fov and setting it in the camera before filming. Color and contrast can easily be fixed in post, same as blur, while sharpness can't be. Judging by the samples, GoPro does a really good job with it's "zooming", so use it.

 

22Apr/120

HDR house..

I was never really a big HDR fan, but I know it can make a great image in certain situations..

d9t8996_hdr
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10Apr/120

Facebook Fan Page

Moj Facebook Page, za vse FB usmerjene osebke ;)
Na strani se bodo redno objavljale novosti, castingi, fotke in debate ter podobne zadeve. V kolikor ste uporabnik/ca Facebooka in me želite spremljati tudi po tej smeri - dobrodošli! :)

My Facebook Page, for all you (us) FB-orientated people out there ;)
I'll be posting news, links, casting calls, photos and stuff like that over there. If you're a Facebook user and would like to follow me there as well - welcome! :)

 

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