Flats problem

[fortytwo]

Hi all,

I've recently tried the white t-shirt method on my SW200 Explorer with my Canon 600 (unmodded).
Two layers of material, exlastic band, no creases and pointed at the day time sky (overcast but bright) facing away from the sun.

The few times I've tried it I get dark areas across the bottom, see below, assuming that shouldn't be there I've used a slower shutter speed to eliminate it to the point it is closed to being overexposed.

I've never had a problem taking flats on my WO73 with an ipad but unfortunately the ipad won't cover the SW200, hence trying the t-shirt method.

Can anybody shed any light....pun intended 😀

Thankyou in advance,

Jeff

 

Edited June 3, 2022 by fortytwo

[michael8554]

You haven't said what exposures you tried ?

It might be shutter shadow if you were taking very fast exposures.

Try more layers until exposures come out at about 1 second with the camera set to AV mode.

Michael

[fortytwo]

On 04/06/2022 at 12:06, michael8554 said:

You haven't said what exposures you tried ?

It might be shutter shadow if you were taking very fast exposures.

Try more layers until exposures come out at about 1 second with the camera set to AV mode.

Michael

Thanks Michael, I think you are probably spot on.

The exposures were 1/4000 so next time I will double up on the layers to four.

I've been using cameras for many years and have never heard of shutter shadow so learnt something new.

Thankyou again,

Jeff

[ollypenrice]

Newts are not intrinsically light-proof in the way that refractors are. Light can enter the scope from the bottom, for instance.

Olly