Flash - Behind the scenes

[Don Hoey]

Very interesting subject FoxyBob.

You are right about flash duration probably 1/10000 sec here.

I know you will like this ....... we need a few tech details of rotor operation. Pics suggest it is hand powered. Therefore speed will be initially high and decreasing. Also difference between winding main rotor and tail rotor.

I think here you used front curtain sync. In this mode the flash will fire immediately the front curtain is open. For the purpose here lets assume a duration of 1/10,000 sec. So if exposure was say 1/60 sec it will be at least 1/59 sec before second curtain moves. During this time exposure is affected by ambient light.

If rear curtain sync is used, situation is reversed. Initial exposure is ambient and immediately before the rear curtain closes flash will be triggered.

The problem if it is hand powered is trying to have the main rotor slowing sufficiently before starting the tail rotor.

BTW very good natural light shot but rotors a bit fast for good prop blurr.

Don

[ollieholmes]

Originally Posted by sassan

# 2 undoubtedly gets my vote. The only question now is how to increase the opacity of moving rotors.

We had this question on an aviation forum and there are so many different ways. Colour of the prop, speed, background colour, painting the tips etc.

[Don Hoey]

This image follows on from my gallery image Lathe Action 2 where I used rear curtain flash sync to partially freeze chuck motion.

In this case flash was only used for that purpose, and only impacted on the overall exposure by a small amount, the main lighting being the workshop lights. Exposure was 1.3 secs at ISO200 at f16. Flash on manual at 1/2 power.

Determining the best lathe speed was a bit of trial and error over the range 210, 300, 420 and 600rpm. The greatest sucess rate was at 420rpm. At slower speeds motion was frozen too sharply. At 600 rpm the freeze was less distinct.

I have attached a composite of the two images that show this technique in action. My feeling is that if this technique is used to reinforce the sense of motion, it works best at an angle rather than straight on. Chuck on the left hand shot is spinning at 300rpm whereas on the right it is 420rpm.

An interesting experiment.

I attach a pic of the cluttered bench layout to give some idea of the limits for composition and lighting.
The tripod ( Benbo ) is strapped down to an ammunition tin full of steel bar ends for stability. Which is seriously heavy as I can only just pick it up.

SB80 flash ( pic attached ) is mounted to my light stand on part of Foxy's " swiss army knife" flash bracket, the current workshop project. Pic of the work in progress bracket as of Thursday evening is in my gallery.

Don

[Ian]

Thanks for showing this I'm following with interest

Ian

[Canis Vulpes]

A day with Don Hoey to take receipt of the amazing flash adaptor shown being constructed above and photographing Nikon's finest and to learn more about flash photography. I am sure many here are in awe of the camera body shots that Don seems to produce with effortless ease. Every time I look at one I think brilliant, simply brilliant - I wish I could do that with the same quality. Yesterday I did just that, in the gallery is my effort supervised by Don. Below is its method and thoughts during its production.

Firstly the two camera bodies are not simply placed on a table then photographed. Almost an hour was spent placing, angling, considering and moving around with a camera and lens looking for that WOW shot. While considering a WOW position I noticed that the Nikon legend on the rear camera was reflecting on the upper LCD display of the front camera. This decided composition; although I had been found by chance I would never found it if I did not sample various positions and angles to photograph using different lenses. Once composition had been decided both cameras went for a good clean and so they were perfect ready for the photo.

Flash lights are added step by step, first is the main light above and left of the subject to generally light the subject using flash adaptor and brolly using shoot through technique. Part of the criteria was to use only my equipment and it was noticed that flash output was a little low by halving the distance doubled the light to subject and adding a second brolly to collect wasted light from the shoot through brolly solved the problem. The main light is now originating from a quasi-softbox much closer to the subject. Another criterion of the day was to bring life to a lens and by placing a reflector/diffuser perpendicular to the front lens element that element approx 15º from camera lens axis did the trick this also bounced light back to the subject. Adding a second flash behind this reflector/diffuser at high power boosted the artefact in the lens element. Lens artefacts depend also on the lens itself the lens photographed is a 17-35mm wide angle which has a large front flat element and bulbous element behind that so little light reflected through it. This lens was selected as it was fairly short and suited the cosmetics of the D2 series cameras in the subject.

The photo took nearly five hours to produce from start to end. All it needs is a Nikon ‘Heart of the image’ slogan and it would look at home in a Nikon dealership.

Photo here...
http://www.worldphotographyforum.com...hp?photo=10599

[Canis Vulpes]

Now armed with a piece of black velvet I have had another attempt at product photography using skills and tips learned with Don Hoey in the reply above.

Setup
I spend nearly an hour setting the scene looking at different angles and compositions. As my velvet was just from the shop it needed cleaning and I found a handy tool shown in pic (1). This tool costs approx £3 from Sainsbury’s sewing isle and very handy for cleaning velvet before the shutter has been released, we have this tool as our cat likes to drop fur everywhere especially clothing. I have taken again to using Nikon Camera control as an easy way of reviewing images on a laptop rather than using the camera rear display or legwork (back to desktop PC). Composition was settled but only allowed approx 30cm working distance pic (2), this limited depth of view so some compromises had to be made. The 17-35 f2.8 I own has a minimum focus distance of around 25cm so I was forced to use this lens at 35mm for the picture.

Lighting
Over the course of this week I came up with a cunning plan to create a softbox using available equipment and with the brolly in shoot through (see above replies) I simply put the silver backing on the brolly in reverse to it reflects any lost light back to the subject pic (3). The brolly soft box as I shall refer it to allows only one light to be used as I needed another light to push life into the lenses of the CCTV cameras. Using camera control flash light and aperture compromise were set and I was happy with pic, stage 2 was to put life into lenses. Using ¼ power manual mode from a second flash unit I added some interest in the lenses but as they are convex aspherical lenses classic ‘life’ could not be put on to them even at full power from second flash. Anymore than ¼ power the overall exposure was affected to much. The amount of interest in the lenses is minimal but this is the nature of the lens not photography technique as the cause.

Please note for setup photographs various items were brought closer and were not positioned as photographed here.

Larger photo can be viewed in the gallery.
http://www.worldphotographyforum.com...6&limit=recent

[Don Hoey]

Foxy Bob,

With a working distance of just 30cm then I am quite amazed at the zone of sharpness you have achieved. Your idea with the reflective part of the brolly ie making a softbox is excellent. As we found when adding a silver brolley behind the white one it frees up a flash unit.

Dabbling with manual flash now !!!

With this quality of pic, and dark wet days in front of us, it will soon be my turn to set a challenge.

Don

[wolfie]

This is all getting very technical, black velvet reversed brollies. So I thought you may find this of interest, a nice little softbox curtesy of Maplins £13 http://www.maplin.co.uk/Module.aspx?...RIES&doy=18m11

I notice with interest that Don is now dabbling with manual flash. Manual is the only way I work with flash, maybe I should become more technical and switch to ETTL.

Now the dark nights are here I've dragged most of my flash gear out, but not the soft boxes or diffusers, Still using the kitchen towelling though.

All my recent experiments have entailed back lighting using several guns, it becomes very interesting, balancing 5-6 flash heads, but it's all good fun as per example.

Harry

[Don Hoey]

Great pic Harry. Always interested in your work as lighting is always top notch.

It is Foxy that is edging into using manual. I can only think in manual and found my SB80-DX instruction manual hard work so gave up on it. Only use DTTL for behind the scenes snaps.

I think manual can appear quite daunting at first, so an easier starter route is ITTL, DTTL, ETTL. Once you are using a flashgun at full bore to get a correct exposure, then you are essentially in manual as metering is having no effect, and only moving the light relative to subject or upping ISO will affect exposure in auto.

The difference between us Harry, is I only have 4 flash guns and 2 slaves and 1 remote cord. Two of the flashguns are battery eaters so most of my shots are with 2 guns only. I will use one of the battery eaters only if I have to.

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

[Canis Vulpes]

I was challenged by Don Hoey to produce a digital version of his brilliant F3 shot ( http://www.worldphotographyforum.com...php?photo=6056 ) using in camera multiple exposure. The challenge was to achieve correct exposure for camera and LCD screen.

After spending considerable time with composition and main lighting I arrived at f20 1/60 ISO 400 using SB-800 at +2.0EV and SB-600 at M1/1 (full power). I imagine SB800 was also was at full power output. Main lighting and composition settled I was ready to experiment with image overlay in camera. Using spot metering on the LCD screen exposure was 1s f20 ISO400 with all curtains closed but when images were combined a small artifacts were present on LCD screen so a black flag was introduced to control any reflection onto the LCD screen of camera with either exposure.

Images below show position of brolly softbox, black flag and camera.

Full size image can be seen in our gallery following the link.
http://www.worldphotographyforum.com...3&limit=recent