worth investing in flash more or teleconvertor more?
i hrd that IQ will be affected abit if use teleconverter for zoom lens, and there will be a few drop in stop or something in term of aperture like from f4.5 to f6?
how does the calculation works?
i have 18-55 f3.5-5.6, 55-250 f4-5.6
if plus a coverter of 1.4 how much long would it turn each into? and how many drop will it drop?
and how about converter of 2.0 how much long would it turn each into? and how many drop will it drop?