{"id":191,"date":"2018-04-03T17:11:08","date_gmt":"2018-04-03T17:11:08","guid":{"rendered":"http:\/\/iebhoreb.org\/proyectos\/wsc-regexperts\/?page_id=191"},"modified":"2021-05-18T23:53:51","modified_gmt":"2021-05-18T21:53:51","slug":"photography-for-honeybee-brood-trials","status":"publish","type":"page","link":"https:\/\/wsc-regexperts.com\/en\/photography-for-honeybee-brood-trials\/","title":{"rendered":"Photography for Honeybee Brood Trials"},"content":{"rendered":"\n

For honeybee brood trials high quality images facilitate the identification of brood stages. Especially eggs and small larvae are much easier to see in high quality images and also automatic recognition of brood stages will perform better. To help to achieve the best images with your gear, an overview is given in the following on how to obtain such photos.<\/p>\n\n\n\n

Resolution<\/h2>\n\n\n\n

If an entire comb shall fill an image, a high resolution is required to clearly see eggs and larvae. Especially young larvae may be incredibly small and hard to see. In general, we recommend using resolutions of 24 MP or more. For smaller resolutions it becomes more and more difficult to visually see the cell content and also automatic recognition rates will drop.<\/p>\n\n\n\n

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18 MP (100% crop)<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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24 MP (100% crop)<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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36 MP (100% crop)<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n

Aperture<\/strong><\/h2>\n\n\n\n

The aperture controls the amount of light reaching the camera sensor (if the aperture is closed by one “F-stop”, e.g. F8 instead of F5.6, half as much light reaches the sensor; smaller aperture corresponds to larger F-numbers). But more importantly, the depth of field is larger for smaller aperture. When using a large aperture (e.g. F5.6) the image will only be sharp at a very specific distance (e.g. only the bottom of cells will be sharp). The top of an old larva, which may be only a few millimeters closer to the camera, may already be out of focus. Closing the aperture will increase the depth of field. Using e.g. an aperture of F11 or F16 will result in images which are in focus both at the bottom of cells and the top of cells.<\/p>\n\n\n\n

Light<\/strong><\/h2>\n\n\n\n
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Brood image with ambient light (not recomended! Do you see the eggs?)<\/figcaption><\/figure><\/div>\n<\/div>\n\n\n\n
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Lighting is a key factor for brood photography. Ambient light is usually insufficient to illuminate the cell content (see image on the right); therefore artificial light is a must. Tungsten light (or LED light as an alternative), which is continuously providing light, has the advantage that the photographer can easily evaluate the light conditions. However, tungsten light is not very powerful; therefore it may be difficult to use smaller apertures than F8. Of course one could increase ISO to increase the sensitivity, but this usually results in grainy, noisy images. Furthermore, generators may be necessary to power tungsten light when used in the field. Flash light usually is much more powerful than tungsten light, facilitating the use of both a small aperture (e.g. F11 or F16) and a reasonably low ISO number (e.g. 100-400). In addition, when using flash and a small aperture, the influence of ambient light is minimized (because of the short exposure of 1\/250 or 1\/60 sec. combined with a small aperture). Therefore, when using flash light no special photo boxes are required to prevent ambient light reaching the comb (which may result in an unpredictable mix of ambient and artificial tungsten light). Finally, a flash is highly mobile.<\/p>\n<\/div>\n<\/div>\n\n\n\n

How to illuminate the combs?<\/strong><\/h2>\n\n\n\n
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Setup used by us (with softbox and reflector, see below for more details).<\/figcaption><\/figure><\/div>\n<\/div>\n\n\n\n
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Typical macro photography setup with two flashes with softboxes illuminating the subject from a 45\u00b0 angle.<\/figcaption><\/figure><\/div>\n<\/div>\n\n\n\n
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Illumination of combs for honeybee brood photography is not easy. One needs to get as much light as possible into the cells to view their content, but at the same time reflections (e.g. from nectar, royal jelly) should be minimized. In macro photography, this is typically achieved using soft light being directed at an approximately 45\u00b0 angle to the subject. This can be done with either two light sources or one light source and a reflector (see image A and B). Usually softboxes are used, because direct light produces hard shadows and more reflections. A large number of softboxes are commercially available, which can be mounted onto flashes.<\/p>\n\n\n\n

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