Reflection and speed/sports

Hi

My name is Bjørnar. Hi
I work as a wind tunnel Instructor. Skydive simulator. And I am having some problems with reflection in the glas, and the movement of the flyers.

So the tunnel is a big cylinder of glass, and the flyers inside are moving quite fast.

So reflection first. The sunlight from the windows are reflecting in the glass of the tunnel. Would love any tips on working around this.

The speed. The flyers pass by fast, so I need a high shutter speed for them not to get blurry. But this makes my photos darker. Again, would love to have a conversation around the topic.

Any advice are welcome!!

Thx a lot!!

Bjørnar

If you have sunlight as your light source a circular polarizer might help you remove the most egregious of the reflections. If the glass is curved you probably cant remove all of the reflections with the filter. It seems to me that you probably want to reduce your dependence on the sun though and use flash to freeze the motion of the flyers. Do you have the capability of affixing a flash in a solid mounting inside the tunnel?

I think an example of a photo you've taken and an explanation of what kind of gear you're using would go a long way towards helping the community help you out.

SkydiveCamera wrote in post #16815846
Hi

My name is Bjørnar. Hi
I work as a wind tunnel Instructor. Skydive simulator. And I am having some problems with reflection in the glas, and the movement of the flyers.

So the tunnel is a big cylinder of glass, and the flyers inside are moving quite fast.

So reflection first. The sunlight from the windows are reflecting in the glass of the tunnel. Would love any tips on working around this.

The speed. The flyers pass by fast, so I need a high shutter speed for them not to get blurry. But this makes my photos darker. Again, would love to have a conversation around the topic.

Any advice are welcome!!

Thx a lot!!

Bjørnar

While waiting for other responses, note that increasing ISO is standard digital camera strategy for underexposure.

I have seen a similar wind tunnel and I think you might want to place a wide angle lens directly against the glass to eliminate reflections. However, if the glass is vibrating from the motor, this will probably not work.

whuband wrote in post #16821127
I have seen a similar wind tunnel and I think you might want to place a wide angle lens directly against the glass to eliminate reflections. However, if the glass is vibrating from the motor, this will probably not work.

This is where the old fashioned flexible rubber type lens hoods come into their own. They allow you to create a "seal" around the glass that will cut out the reflections you don't want, without picking up too much vibration from the fan motors. You will need to up the ISO value to enable you to use a shorter shutter speed to freeze that action. Really you need to use a shutter speed of 1/500 or even better 1/1000 or even faster if you can.

My suggestion for camera settings would be to use Av mode. In this mode you set the value of the lens aperture. Set the lens to the widest aperture your lens has, that is the smallest number. On most kit lenses supplied with DSLR's this is likely to be between f/3.5 and f/5.6. Set the ISO to the highest non expanded (Not H, H1 or H2). This will always give you the fastest shutter speed for the lighting conditions you have at any time. If the Shutter speed indication is flashing at 4000 or 8000 (depending on camera model) then you need to reduce the ISO by one value until the indication stops flashing, or the shutter speed drops a little below the maximum.

An example would be useful as would knowing what camera/lens combination you are using.

Alan

Hmm, some clarity from the OP?

When you say "The sunlight from the windows are reflecting in the glass of the tunnel.", are you referring to light reflecting off the outer glass surface, or are you referring to light going through that glass and bouncing off the "inner" glass surface, in other words bouncing off the side of the tunnel across from you so you see the reflection coming from the inside (rather than bouncing off the direct side of the glass that you are standing at?

I want to not sound verbally confused...kind of like standing at a fish tank where light is bouncing off the outside and you can "fight" that by squeezing your lens/lens hood against that glass, but then on the opposite side of the tank light is also bouncing/reflecting, you are "seeing" the reflection quite clearly!

Now of course we have Circular Polarizing Lenses/Filters, but they will slow down the shutter speed or force a wider aperture, and still may not be all that effective if it's the "inside" reflection we are discussing!