Extension Tubes And Bellows The Problem Of Exposure Compensation

Extension Tubes And Bellows The Problem Of Exposure Compensation

Bellows and extensions reduce the amount of light that reaches the sensor, this may require a compensation in order to obtain the desired result. If you are equipped with a TTL flash, this can be used to compensate for the loss due to the extension, but be careful what you photographed a flash goes well in the studio, but photograph a bug and shoot in the eyes a flash is not exactly the best of life (as well risk it run away).

Find the right compensation, if you do not have a TTL flash, it is not complicated

Compensation factor = measured exposure  (M + 1) 2

In the case of a 1X magnification, the compensation value to be taken into account will then be equal to Esposizine measured  (1 + 1) 2 = measured exposure  4 http://akusaraprosound.com. In practice I will need to provide four times the read light, or I will have to open the My aperture by two stops (and thus, for example, switch from f  16 to f  8) .Another solution to obtain a macro lens is to mount a lens on the contrary, operation feasible using the reversing rings.

A solution alternative to the use of the close-up lens is given by the use of extension tubes tubes it is devoid of the objective lens that physically distanced from the sensor. The greater the length of these tubes, the greater the magnification. Just to give a measure of magnification change, remember that

Focal Length  (M + 1) = Distance between the lens and sensor (V).

M is the magnification. To give an example, assuming a 1X magnification, a 50mm objective would require an extender 100mm V = 50  (1 + 1) = 100

The extension tubes, however, have a problem not to be underestimated because of their length drastically reduce the amount of light that reaches the sensor. Eye also to buy one that can transmit electrical signals for autofocus.

An equivalent solution to the extension tubes are the bellows extenders it comes to extension variables tubes and therefore adaptable to various situations. While they are flexible, the other almost never replicate the electronics and their use is not exactly trivial. Tare the right length for the magnification required is not an easy task to do, especially for those who are beginners. By the way, on the principle of the bellows it is also based the lens-baby lenses even though the concept to extremes by allowing a much greater mobility than just fire board.

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