Great Question from our Fundamentals I Workshop… apertures…

… Today, I received an email from one of the students from the workshop this past weekend. The question was dealing with aperture choices in variable aperture lenses. The student wanted to know that if he was using a lens, such as an 18mm to 55mm lens, with a variable aperture of f/3.5-5.6, could he use any other apertures or was he confined to using only f/3.5-5.6?

This is a good question because lenses with variable apertures can be quite confusing. For one thing, let me talk about variable apertures, first. If you are not familiar with them, a variable aperture lens is a lens in which the largest aperture does not remain constant as you go from the widest focal lenght to the narrowest focal length. In a lens such as an 18mm-55mm f/3.5-5.6 lens, the largest aperture would be f.3.5, but it would only be that large at its widest focal length, which is 18mm. But as you zoom from 18mm to 55mm, the aperture would get smaller in relationship to the focal length of the lens. So as you zoomed to 55mm, the aperture would go from a somewhat large aperture of f/3.5 to a moderate aperture of f/5.6.

Now if you have a lens in which the aperture remains constant at its largest aperture, as you zoom from wide angle to telephoto, than you would have a constant aperture lens. One of my favorite constant aperture lenses is my Tamron 28mm-75mm f/2.8 lens. If I choose a large aperture of f/2.8 and shoot at a 28mm focal length (its widest angle focal length), my lens would allow for me to remain at f/2.8 as I zoomed to a 75mm focal lenght. I would not lose light as I went from wide angle to telephoto. This is one reason why constant aperture lenses are considered more professional lenses.

Now, going back to my original point, aperture choices. If you are using a lens with a maximum aperture of f/2.8, that means that your largest aperture choice is going to be f/2.8. You will not be able to go a larger aperture than that, such as f/2.0 or f/1.4. However, you should be able to select smaller apertures such as f/4.0, f/5.6, f/8, etc. The only exception to this would be either a mirror lens or a broken lens. Now, if you have a variable aperture lens, such as a f/3.5-5.6, that just means that you will not be able to use an aperture smaller that f/3.5 at any focal lenght, and you will not be able to use an aperture smaller than f/5.6 at its most telephoto focal length. You should still be able to select smaller aperture than f/5.6 at every focal length.

Now, I use to shoot with variable aperture lens. That was mainly because when I started out in photography, I did not have the knowledge, or more importantly, the money, to own them. But I did a purchase a great quality lens a year or two after I started learning photography. I bought a Canon 17-85 f/3.5-5.6 IS lens from Peace back in 2005 or 2006. I have to say, I loved that lens. Sure it was not a constant aperture, nor did it let in alot of light. But it did have a great focal length for my Canon 20D, at the time. Plus that baby was sharp! Unfortunately, once I got serious about using studio lighting equipment, it became somewhat of a pain having to readjust the lighting everytime I zoomed from wide angle to telephoto, that is when I was lighting to shoot it at the largest aperture.

That meant, that if I wanted to shoot for the shallowest depth of field, I had to shoot at the largest aperture. In this case it would have been f/3.5. But, I could only shoot at that aperture when I was shooting at a focal length of 18mm. However, if I wanted to zoom in tighter, it would cause my aperture to close down to an aperture of f/5.6. If I was using the studio lights as my key light, that meant that I was now One and a half stops less that what my lighting would have been set for. So, that would require me to go and adjust the lights to match my camera’s exposure. Let me just tell you, it was a total pain! That’s one reason why I would usually just set my lighting to expose for f/5.6 or f/8 because I knew that I had both of those apertures available at all focal lengths.

Well, even though I loved that lens, I was incredibly happy to part with it once I started shooting with constant aperture lenses. So, here are a few of my favorites…

  • Tamron 17-50 2.8 VC (Canon and Nikon) – I own this one, and love it
  • Tamron 28-75 2.8 (Canon, Nikon, Sony, Pentax) – Own this one, too – Great lens for full frame cameras such as the 5D or D700
  • Canon 24-70 2.8 L – Use to own two of these when I was shooting Canon. I liked it, but considering the Tamron is just as good, and at least $1000 less expensive, I just say buy the Tamron.
  • Nikon 24-70 2.8 Nano – See above 🙂
  • Canon 24-105 f/4 L IS – This became my favorite walk around lens when I was shooting with the Canon 5D. Its an awesome lens, very sharp, fast focusing, and a great price.
  • Nikon 24-120 f4 VR Nano – I dont own this one, but if anyone wants to buy me this as a farewell gift, I will gladly accept 😉 – But seriously, its about time Nikon finally got this lens right. Nikon had way too many 24-120 lenses, but none of them were constant aperture lenses, and they all kinda stunk. This one ROCKS! It came out last October, and I want it so badly.
  • And of course, the Canon 70-200 2.8 L IS and the Nikon 70-200 2.8 VR – I just put both of these together because if you are shooting with Nikon, and you can afford it, buy it! Same goes for Canon. I owned the Canon one, and loved it. Now I am shooting Nikon, so of course it was the first one I purchased when I switched over. Some might tell you to get the Tamron, and save money, and I would agree. However, for the extra cash it costs to get either the Nikon or Canon, it is worth it. The added image stabilization is worth it. When you are trying to track movement, having VR or IS can really help out.
  • And last, but not least, the Nikon 14-24 f/2.8 – Well this is the lens that really convinced me to go Nikon. I use to own the Canon 16-35 f/2.8, and I never really liked it. But this one does to the Canon what the Globetrotters do to the Generals. I will mention one other lens, the Tokina 16-28 f/2.8. This lens just came out, and its harder to find than Amy Winehouse in a Jenny Craig convention. But, this lens is well worth the hunt, and at least it will not smell like booze and crack once you find it.

Well, that’s about it. Hope this was helpful. If you have any questions, please let me know. And remember, with my future freetime, expect to start seeing this blog grow. Not only will I be including some helpful articles, but I will also start documenting my shoots. You will see some cool photos coming up soon, from a few of the past weddings I have been lucky enough to shoot, too. And once I get down to Florida, you will see some new shoots that I have started planning, come to light. So, please support me, and follow me. It will be worth it.

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