More purchases and a little about F-stops!

Around this time I made a number of new equipment purchases for my photography:

Hama shutter release cable

I bought a Hama release cable - this was basically to make up for the fact that the NEX-3 (unlike the NEX-5) doesn't have infra red remote trigger, and so long exposure shots where we required no movement at all, are affected by a button press. Attaching this simple but effective device seems to get around this and reduces (though to be honest still doesn't fully eradicate) trigger wobble. 

LowePro Fastpack 250

Another investment, and one I love to bits, is the LowePro Fastpack 250 rucksack - this is designed to hold your camera and a number of different lenses and other equipment in the lower 2/3rds of the backpack with side entry panel for easy access to your camera. There is also a top section to hold other items and a laptop section, erm, to hold your laptop. I have to say this bag is perfect, it holds all of my photography equipment and when I travel I simply remove the items I don't need, add my laptop, and take this as my hand luggage. I love it!

Minolta AF75-300 telephoto lens

The final purchase I made was a new lens (well, I say "new", it was new to me, I bought from ebay for a price I could justify for this experiment). This was the Minolta AF 75-300 telephoto zoom lens. You may ask why? Simple, because I was trying to take pictures of birds in the back garden and decided that my Sony SAL-55200 lens couldn't get close enough and I must therefore need a lens with more zoom. This lens was 75-300 instead of 55-200 so of course had greater zoom and was therefore better right?


Well, my basic theory was of course correct, the lens turned up and I was delighted to see that yes I could indeed zoom in a little closer on the subject.
However, it turns out I was wrong, it took me a while to realise it and lots of bird shots, and then I finally sumarised that this lens was not as good as the Sony SAL-55200. Yes it zoomed in further, but the pictures were never quite as good. I decided I needed further investigation!

Birdwatching through the Sony lens

Birdwatching through the Minolta lens

At first I concluded it was down to the lens' F-stop ratings. The Sony lens has F4-5.6 and the Minolta has F4.5-5.6. I thought to myself, the 2 numbers must represent the best and worst F-stops the lens is capable of and therefore the Sony lens is capable of F4 rather than the Minolta which is only capable of F4.5. Everybody knows that the lower the number, the "faster" the lens, and so it is capable of letting in more light, this must be the reason the pictures didn't look as good through the Minolta.


Nope, wrong again, I finally did some more investigation and found out that the F-stop ratings represent the best possible F-stop rating at the 2 ends of the zoom scale. So the Sony SAL-55200 (F4-5.6) is capable of an F-stop of F4 at 55mm and F5.6 at 200mm. The Minolta 75-300 (F4.5-5.6) was capable of an F-stop of F4.5 at 75mm and F5.6 at 300mm. So at their furthest zoom reach, both cameras managed and F5.6 and therefore for this situation were both the same. Yes at the un-zoomed end of the scale the Sony lens was faster but I was trying to capture birds whilst totally zoomed in so this was irrelevant.


Much more investigation down the line and what I concluded (with no real proof or evidence) is that the Sony lens was simply better quality. It would seem that a better quality lens costs more money because of the quality of the glass (materials and shape), the number of elements, good multicoating of all the elements, quality mounting, quality manufacture and assembly. You cannot base the quality of a lens on the statistics attached to it and whilst F-stop ratings and other such things are indicative of a lens' potential, the potential is only as good as the quality of the lens! Many months further down the line I realised this and now have pretty much stopped using the Minolta lens in favour of the Sony. 


This of course didn't solve my problem, Sony do make a 75-300 lens for the same price as my 55-200 but that is a little more expense than I'm prepared to play with and they also of course have similar lenses for a lot more (silly) money which I'm not going to stretch to. Instead, the simple and obvious solution, is to move myself closer to the birds. I could invest as little as £60 in a bird hide and just sit and wait for the pictures or alternatively I have realised that the longer I spend sat in my garden the more tame the birds become and I can simply sit closer to them! :)

Birdwatching through the Sony lens close up!