Set fixed focal length with a zoom lens

CaptainCaptain

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Hello everybody,

I am new in the camera world and have relatively little idea. Now I need a system camera for technical applications and the following question arises:

Is it possible to fix the focal length of a zoom lens, e.g. the E 16-50mm 3.5-5.6 OSS or the E PZ 18-105mm 4.0 G OSS? So to say that it should be exactly 35mm? Or is the adjustment of the focal length more a rough estimate?

The reason I ask this, is because I need some fixed focal lengths, but several fixed focal length lenses would be too expensive too buy and therefore I want to try it with a zoom lens now.

Thank you in advance
 

bdbits

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Bob
You can see the focal length you have set as you are changing it. How easy it will be to land on the exact one you want - and how accurate the readout is - is harder to say. Even fixed focal length lenses can often be a few millimeters off from and exact measurement, e.g. my Voigtlander 40mm/1.2 is actually about 43mm say people who are a lot smarter about such things than I am.

What is your application? Why the need for such a precise focal length? If you are just trying something or its a hobby kind of thing, does it have to be so exact? Maybe if it becomes serious enough, it will generate some income and you will be able to swing the cost of the fixed focal length lenses.
 

WNG

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Will
Hi, welcome! Yes, any zoom lens with the range desired can be set to the most popular focal lengths. Even the power zooms. The preciseness and convenience won't be as simple as manual zoom rings, but you do see a display on the LCD or EVF of the focal length.
Bear in mind, you only get the focal length of the prime, not the light transfer characteristics of the prime, ie. aperture, T-stop. If a prime is a f/1.8, and your zoom can only do f/4, well, the end result will look different.
 

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