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Good afternoon, I have tried every setting on my Sony DSC-H400 to stop the flash reflecting back off the glass of my subject. I'm new at this! I have read through all my books.Jane

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  • \$\begingroup\$ Thank you for all your comments. Today so have spent time practised with all options. It is difficult but It has been, and will continue to be a challenge. Thank goodness we don't have to pay for film! I will be stuck on this for a while me thinks. \$\endgroup\$
    – user53760
    Jul 10, 2016 at 20:03
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    \$\begingroup\$ Can you answer some of the questions? What kind of glass did you mean? \$\endgroup\$
    – mattdm
    Jul 10, 2016 at 20:11

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Good afternoon, I have tried every setting on my Sony DSC-H400 to stop the flash reflecting back off the glass of my subject. I'm new at this! I have read through all my books.

I originally assumed you were referring to subjects in glass protected display cases, and that's what the second part of my answer refers to. The 1st part below refers to taking flash photos of people wearing spectacles.


Flash photos of people wearing spectacles:

The main problem is that the spectacle mirrors and reflect the light.
If the flash is mounted on the camera and pointed at the subject then light will be reflected back into the camera.

(1) The most complete fix is to not use a flash and use other 'ambient' illumination whose reflections can be better controlled. This may not be practical.

(2) In place of a flash it may be possible to use an external light source.
Use of eg an LED lamp can help as you can adjust its position to move reflections out of the scene. If the subject is moving (eg fish) flash is often helpful.

(3) If flash & spectacles are unavoidable then something along the lines covered in my "glass case" situation may be suitable depending on circumstance.

(4) A flash based solution that works quite well but takes more work is to use an external flash triggered by your camera. An external flash can be located some distance to one side of the lens axis so that reflection return at an angle and do not enter the lens.

As your specific camera does not have an external flash connector less standard method are needed. Many flashes, including some low cost ones, can be triggered optically by the flash from another unit.

What I do on occasion is use an on / in camera flash set to manual low power, then diffuse it with paper or cloth of a formal diffuser so that the light reaching the subject directly is small. I mount an external flash either independently mounted or on a bracket that allows 100mm+ spacing away from the left side of the camera. While this results in manual flash operation it is useful enough in terms of power and off axis angle To be worthwhile.

Optically flashes will usually operate in manual mode - meaning that you must set the brigthts level manually. This is not as good as having automatic exposure adjustment but is still very useful and quite easy to get used to.

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Flash photos through glass in display cabinets etc.

My answer here and other answers to that question there MAY help depending on your situation. The answers in 1. above are generally applicable.

If you can mount the flash some distance from the camera so the camera does not 'see' the flash reflection directly it can help greatly.

Here is a summary of my above cited answer (with some additions) but do look at the original.

(1) Place the lens face close to the glass if possible - maybe one foot or less.

(2) Arrange the camera so it's axis is at a significant angle to the glass, so that reflections from the flash are reflected away from the camera and completely out of the scene. I usually photograph from the side but best angle depends on subject and circumstance and horizontally or vertically angled or in between is OK.

(3) Set camera so that the non flash illumination is low compared to the flash illumination. Probably at least F/8 and a smaller or much smaller aperture can help. (Too small (f/22?) and you start to get softening due to diffraction. How small is too small depends on the lens.

(4) Experiment.


This photo 2000 years! - Xian

Temporary image while link self-repairs (hopefully).

enter image description here

was NOT taken with flash but there was a thick glass security cabinet (the display is priceless) and multiple halogen lamps from various angles making photos from any distance very poor.
I placed the lens essentially against the glass at an angle and shrouded my head and camera with a jacket so that there was no external light around the camera. I have some good "with flash" through glass examples which I will try to post a sample or two of.

If distance to glass is substantially lower than the lens focal length imperfections on or in the glass are defocused. They still degrade the image but usually only as somewhat reduced contrast if not too severe. (Needless to say I clean the glass well whenever possible.)

Angled flash works well for eg museum and similar display cases where flash is allowed. You can almost always get good photos of static subjects behind glass without using flash. Colour balance needs to be adjusted to suit. Use of an LED lamp can help as you can adjust its position to move reflections out of the scene. If the subject is moving (eg fish) flash is often helpful.

editing

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  • \$\begingroup\$ The photo yoi linked called "2000 years! - Xian" is link dead \$\endgroup\$ Dec 9, 2018 at 12:06
  • \$\begingroup\$ @Santropedro Thanks for the warning - that was caused by my Dropbox account not working for some reason. I have added a temporary image. I note that despite prior promises to the contrary the site is claiming the legal right to steal images included in posts. I don't know when this execrable practice was reinstituted. No reputable sites allow such actions. \$\endgroup\$ Dec 9, 2018 at 12:45
  • \$\begingroup\$ @RussellMcMahon but by uploading the image, you agreed that SE and Imgur have the right to host and display the image. So they image that is displayed (with your watermark and "not cc by sa licensed") actually is CC-by-SA licensed, correct? Ceci n'est pas une pipe, non? \$\endgroup\$
    – scottbb
    Dec 9, 2018 at 13:27
  • \$\begingroup\$ @scottbb IANAL - but I am aware that SOME US lawyers would attempt to argue the point. I suspect that the Open Software Foundation MAY side with me against themselves if it came to that :-). I was, and am, making a point which should be appreciated by anyone in SO/SE management who cares about their fodder-base (thus invoking "No true Scotsman" :-). Probably now several years ago I took this point up with 'management' and was assured that the CC... assignment was an unintended mistake, that it applied to free Imgur images but not to ... \$\endgroup\$ Dec 10, 2018 at 11:09
  • \$\begingroup\$ ... paid Imgur accounts, that SE fell in the letter category, that they had no intention to steal my/your/our IP AND that they would adjust things accordingly. AFAIR they did. Someone(s) appear to have unadjusted it. The reason that my link (presumably made in 2016) went to a dropbox account and not to Imgur was due to the original issue. It's likely that I somewhere have a copy of my original correspondence with SE on this and it is also AFAIR in a meta question that I raised. \$\endgroup\$ Dec 10, 2018 at 11:16
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The advice in the other answer is good, but something you could also consider is a polarising filter - adjusted to the correct angle, these can be good at dealing with reflections. Place the filter in front of the lens, and take some test shots rotating the filter until you get a good result.

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  • \$\begingroup\$ Something to try, not to rely on :) Also, a funny thing will happen with some brands of sunglasses :) \$\endgroup\$ Dec 11, 2018 at 15:55
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What you're trying to avoid is any light from the flash reflecting off the glass and into your camera. It's an angles game. But because you're using a bridge camera's pop-up flash that is fixed in position just above your lens, it's going to be very difficult to get all the light to reflect off of glass (or glasses) at an angle the camera can't see.

In studio lighting situations, the flash is separated from the camera and the angle of the light can be more controlled. If a subject is wearing glasses where you don't want reflections, you have them face to their right, while you light them from the left or vice versa. But since you're using a pop-up flash, you may never be able to get the angle wide enough not to have some reflecting coming back to your lens.

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