JonPatrickHyde
2 years ago10,000+ Views
What is the Difference Between Straight and Curved Blade Apertures?
ABOVE - Me shooting the Nautica/Malibu Triathlon benefiting the Children's Hospital Los Angeles in Malibu, CA this past weekend with a curved blade aperture Nikon AF-S 500mm f/4 lens and my Nikon D4s.
Camera lenses all share certain design characteristics which are dictated by their function and the properties of light and more importantly capturing it. Aperture construction has remained similar for the past 100 years. Most sources you will find state that both curved and straight blade options have been around for just as long. The advantages of one over the other are debatable. It is a known fact of photography and light physics that the shape of the aperture is represented in the out of focus areas of the frame, especially in the representation of light sources. Straight blade apertures produce polygons. Rounded or curved blade apertures produce circles or circular shapes. In terms of aesthetics and the recent focus (sorry for the pun) on "Bokeh" - or the quality of out of focus elements of a photo (i.e. are they pleasing or distracting); the general consensus is that the more soft and rounded the bokeh highlights, the more pleasing the effect. The most common explanation for the use of straight blades over curved has to do with the cost of manufacturing (curved blades are more expensive to produce - thus the recent assertion that lenses with straight blade apertures are "cheaper" than a lens with curved blade apertures). I haven't seen any hard data confirming this; either way there are professional lenses which cost upwards of $10,000 US which utilize one or the other. In the case of professional Super Telephoto Lenses; none of these lenses are "cheap". This past weekend I shot coverage of the Nautica/Malibu Triathlon with two high-end professional Nikon Super Telephoto Lenses - the AF-I 300mm f/2.8D IF ED (straight blade aperture) and the AF-S 500mm f/4D IF ED (curved blade aperture). BELOW - A side-by-side comparison of two images at the same angle of view during the cycling portion of the triathlon - shot in the same location - HWY 1 (The Pacific Coast Highway).
WHICH IS BETTER? I can tell you that Bokeh aside the AF-S lenses (powered by focus motors inside the lens) are superior to the older AF-I (sometimes called AF-D) lenses which have to be powered by the body (through a port connection between the body and the lens). The tracking and focus speed is night-and-day different. That being said the optics in both are amazing sharp and crisp. The level of color representation and detail is unquestionably beautiful. The difference in the shape of the out of focus highlights may or may not be an issue for you aesthetically, so the difference in the lenses comes down to two factors - economics and speed of focus. The price difference between the two can only be compared on the used market - because both the AF-I and AF-S (non VR) lenses are no longer manufactured. With the AF-S used models running nearly twice the cost of the AF-I models; the difference in their price may be the difference in owning a professional Super Telephoto or not. If you can afford the AF-S, I'll tell you to always get it first. The frustration that you'll save in experiencing focus to shoot time over the AF-I is worth the price if you can afford it. If not there's absolutely no shame in getting the older AF-I /AF-D models. Just be careful. Some of the AF-I/AF-D lenses are nearly impossible to get replacement parts for since Nikon stopped manufacturing them (the dates are fuzzy with some sources saying they stopped making replacement parts in 2005 and others saying before). I own a pristine AF-I 300mm f/2.8 because it was the ideal lens for my Nikon F-5. The combination of this lens with any Nikon DSLR that has the internal focus motor (body) is stunning - polygon bokeh and all.
ABOVE - Earlier in the day at the 2015 Nautica/Malibu Triathlon (I hadn't broken out my "lucky" hat to keep the sun off me yet), shooting the first part of the day with my older but optically amazing AF-I/AF-D 300mm f/2.8D IF ED lens.
IN CONCLUSION - Which is better? The quality of the image where the point of focus is concerned is identical. Both the AF-I/AF-D lenses and the AF-S lenses are incredibly sharp and color representation is phenomenal. Where the two differ is in the handling of the bokeh (the out of focus elements of the frame). The AF-I/AF-D lenses produce a clear 9-sided polygon shape and the AF-S lenses produce circular (although they are more football shaped than round) bokeh. In the next card I'll do a thorough comparison of these two amazing lenses and get into the fine details of their construction, functionality, focus abilities, and overall image quality. What do you think? Of the two examples (the shots from the race showing the bokeh shapes), which is more appealing to you? I'd love to hear your thoughts!
© Copyright 2015, Jon Patrick Hyde, All Rights Reserved. Photography & Cinematography 101
5 comments
I personally (and this is knowing nothing at all about photography) think the curved blade lens is better. It's a little hard to explain, but the straight blade picture looks more to me like a photogrpah, with the polygonal background, while the curved blade photo looks as near as I can imagine to what my eye actually percieves. it makes more sense looking at it, it feels more familiar, in a way. does any of that make sense? I'm certainly no expert. I'm not even really an amateur.
2 years ago·Reply
These photos are incredible. I would love to learn to shoot my own stuff and this card will totally help with that. There is so much preparation that goes into this sort of thing and you really do a great job of explaining that. I'm excited to learn more from you @JohnPatrickHyde !
2 years ago·Reply
to me the below picture looked a little bit sharper. but it's super close
2 years ago·Reply
your pictures are amazing
2 years ago·Reply
@VinMcCarthy - I agree with you. It's the same argument (sort of) that I use in the negative/film vs. digital argument. Digital images are comprised of pixels - which are square or rectangular (depending on the aspect ratio) - film consists of layers of silver halide - which is circular in shape. This is important because grain patterns are created by both negative and digital formats. And I think we accept - subconsciously - film easier because the random patterns of the grain are natural looking. Why are they more natural looking than digital grain? Name one thing in nature that grows as a square... Nature favors the sphere - the circle... from stars and planets to fruit, raindrops, and the shape of your pupils... the circle is the natural form. Rectangles and squares - outside of some very rare mineral formations - are not common. I agree - the circular bokeh is more pleasing to me. @TessStevens - Thank you! I'm going to post a series of them. It was a star-studded event... what's cool is Jeffery Tambor was the MC for the awards ceremony and he told me he had to get going so he could get to the Emmy Awards on time... he was nominated but sincerely didn't think he'd win - and HE WON! I was so happy for him. He's such a pleasant, funny, down to earth gentleman. And he's hung out with Hellboy! :D And thank you for the compliment on my sharing... knowledge is power. And I do not think it should be horded or kept hidden away... I love sharing what I've learned. I have a butt-ton of student loans... I went through college 20 years ago and paid those very few loans off... I was lucky that my parents paid a lot of it... when I decided to go back to school at age 37, I wanted to focus on school and nothing else. I only had 2.5 years of school to graduate because I'd done core classes before and they counted. But still... the school I went to was one of the most expensive in the USA, in one of the most expensive places to live (Santa Barbara). I did soak up EVERYTHING I was taught. I love photography. I love the science, the technical aspects, the gear (I'm so stupid for equipment) and the artistry. I love the timing and rhythm... all of it! And if I can share what I spent a small fortune to learn with others and it help them enjoy photography in any way... that's what makes it all worth while to me. Sharing information that you are passionate about is (in my opinion) the best way to help make the world a better place. Let's talk about positive, happy stuff. And not focus so much on everything that we don't like. @buddyesd - Totally! With both lenses - they're basically telescopes... so a cyclist moving 25mph comes into range and moves out of range quickly. I was joking with another photographer there (with a much smaller lens than mine) - he said, "You can really see their face perfectly!" I said, "I can see up their nose if I angle it just right!" LOL. @raenel - Thank you so much! I'm glad you enjoy them!!! :D
2 years ago·Reply
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