The importance of "good" glass?

[stuartv]

I've been pondering this for a while. In photography circles in general, you always hear people talk about the importance of good glass.

I tend to associate "good" glass with being fast. I.e. f/2.8 or bigger.

But, I generally just shoot WA and CFWA. So, I am almost always using f/8 (equivalent) or smaller/slower.

In that case, is there really any benefit to buying "better" glass? If I'm always going to shoot it at f/8 or smaller?

To be specific: I'm shooting an m43 camera with the kit lens. I did upgrade from a cheap wet wide angle dome to a good one (a Nauticam WWL-1). That did make a really nice improvement in image quality. By my actual lens is still the $100 kit 14-42 f/3.5-5.6 lens and I'm almost always shooting it at a focal length of 14mm (FF equiv. to 28mm) and f/4 - f/5.6 (FF equiv. to f/8 to f/11).

If I were consistently shooting at, say, 18mm, would it really improve my images to change from the kit lens zoomed to 18mm to a nice 18mm prime (just for example). Same focal length. Same f/stop. Better picture?

 

[aviator8]

I've been pondering this for a while. In photography circles in general, you always hear people talk about the importance of good glass.

I tend to associate "good" glass with being fast. I.e. f/2.8 or bigger.

But, I generally just shoot WA and CFWA. So, I am almost always using f/8 (equivalent) or smaller/slower.

In that case, is there really any benefit to buying "better" glass? If I'm always going to shoot it at f/8 or smaller?

To be specific: I'm shooting an m43 camera with the kit lens. I did upgrade from a cheap wet wide angle dome to a good one (a Nauticam WWL-1). That did make a really nice improvement in image quality. By my actual lens is still the $100 kit 14-42 f/3.5-5.6 lens and I'm almost always shooting it at a focal length of 14mm (FF equiv. to 28mm) and f/4 - f/5.6 (FF equiv. to f/8 to f/11).

If I were consistently shooting at, say, 18mm, would it really improve my images to change from the kit lens zoomed to 18mm to a nice 18mm prime (just for example). Same focal length. Same f/stop. Better picture?

Good glass is a broad term. Certainly wide apertures are considered in deeming lenses good or not, but other factors also contribute. sharpness over a wide aperture range is one. Every lens will have a sweet spot at a certain aperture were the images are the sharpest, in good glass the sweet spot is wider. There is also edge softness in comparison to center sharpness. In my view one of the biggest benefits of pro level lenses is color rendering. When I got my first Canon L series lens the difference in color I could achieve over the kit lens was quite noticeable. For land based shooting, wide apertures get a lot of focus to get shallow depth of fields and good bokeh. You are correct that this matters less in underwater photography. I would say that seeking out Pro level glass is still desirable for the other reasons I list which apply equally in the water as much as on land.

 

[Chris Ross]

The WWL premise is to use kit lenses behind a specially designed wet lens and this results in sharper images than the best pro zoom lenses behind a traditional dome. This says to me that dome optics degrade sharpness significantly. If you tested the recommended lens to use behind the WWL or WACP like your 14-42 and 28-70 f3.5-4.5 from Nikon/Canon compared to the pro 16-35mm equivalent lenses (f4 or f2.8) in air the the pro lenses would have an edge. In theory your 18mm prime might be better still as long as it met the criteria for the wet lenses which is maximum of 28mm full frame equivalent focal length and front element diameter no bigger than that of the 28-70 lens listed above. For example you can't use the 28-70 f2.8 lenses behind the WWL/WACP as the front element is too big. You also need a suitable flat port.

If you are talking WA zooms in a traditional dome port, there is generally no advantage to the f2.8 version to the f4, the modern f4 zooms are every bit as sharp as their big brothers these days and you never shoot at f2.8 behind a dome.

For your WWL and m43 camera you can refer to the compatibility chart for lenses that have been tested: https://www.backscatter.com/images/article/content/wwl-1/83201-WWL-1-Port-Chart.pdf

I assume you are thinking about lenses like the Oly 17mm f1.8 - it may work but you'd have to work out what flat port it would need to go behind and test it for your self - I would assume there are certain criteria for how close the front element needs to be to the port glass but I'm guessing. It may or may not work well. It certainly is not listed in the WWL chart linked above.

 

[HKGuns]

It all depends on the amount of light. My 500/F4 takes astounding pictures and can keep up with fast action even in fading light.

For your type of photography, distortion is a good measure.

I think you may also be missing out on using smaller apertures to experiment with depth of field, which can make macro photography far more interesting and challenging. At smaller apertures the quality of the glass makes a huge difference, even in macro shots. No reason to use F8 for Macro exclusively. Here is a great example of using DOF to blur the background and make the subject pop. Not quite macro, but similar to what you shoot.

This is taken with the good glass of my 500/F4.

This one was taken with my 85/1.2 similar effect but very different focal lengths and distances.

 

[davehicks]

Good glass is still a thing in underwater photography, but I think the criteria are going to be a lot more specific. The lowest f-stop might not be that criteria, but sharp, fast, and accurate autofocus are critical. Performance behind a dome port is the biggest variable. There are A+ lenses (on land) that are crap under a dome with soft corners. Some lenses to well with a smaller dome, others won't tolerate anything but the most gigantic 9" dome. The best advice I have it think about what sort of images you are hoping for, and do some research on your camera as employed by other photographers UW.

 

[Interceptor121]

Prime lenses have no use underwater in broad terms
People have used lenses like the tokina 10-17 with much better results than expensive rectilinear lenses because dome port optics has much more impact.
I use a micro four thirds the lens to go for cfwa i use some time at f/4 but mostly f/5.6-f/8
I then have a kit zoom lens with the wwl-1 that I only use underwater and also a pana leica 8-18mm only use at f/8 for splits or wreck interiors.
In essence I run two sets of lens for land or water use. The 8-18mm used in both and sometimes also a 12-60 but rarely. For macro instead you will shoot at f/2.8 but then focus ability is more critical for example the lana leica 45mm is hard to use compared to the oly 60mm even if 45mm would be ideal
If you had to look at changing your 14-42mm with a prime you will not find sharper options anyway and the sharpness of the 8-18 behind a dome in corners is less than the cheap kit lens with the wwl-1

 

[stuartv]

Thanks, everyone for all the good insights.

The question was posed as more theoretical for me. I'm not planning to buy any new glass for my current rig. I used it as an example just to provide a concrete example of a possible scenario.

In reality, I am going to upgrade to FF sometime this year. My current camera is pretty old, at this point, and the AF tech in it is just not nearly as good as newer top shelf stuff. Even using new glass with it would mean buying a whole new housing, as my Meikon housing is a fixed port. No point in spending all the money for a new camera and housing unless it's going to be a significant upgrade in capability or image quality. So, I will stick with what I've got until I can afford a FF camera and housing.

So, my takeaway from all this is that, as a general rule (for underwater shooting), "good" glass is not necessarily better. It's the combo of the lens and the dome/port that matters. A "lesser" lens with a good dome or port might actually produce better results than a "better" lens, if the dome/port for the "better" lens isn't a good match.

Again, thanks to you all for taking the time to hit me with some knowledge.

 

[Hoag]

@stuartv, I have what some would consider far too much money invested in photo gear, and yes, I belong to that group of people that swear by "good glass". I have never thought of it in terms of f stop to any great degree. When I shot Canon, one of my favorite lenses was the Canon 24-105mm f4 L IS USM. It had a constant (f4) aperture throughout the zoom range, it was razor sharp, the focus was fast and accurate and it had very little distortion. It was not an f2.8 lens, but it was arguably one of the best lenses that I have ever owned and was on my camera about 90% of the time. I also had an 18mm f3.5 Zeiss Distagon Lens. Again, this was not an f2.8 lens, but the sharpness and the colours were IMHO second to none. On the other hand, I have also had lenses that were f2.8 that were, as one friend put it "as sharp as a spoon full of peanut butter".

Now, I shoot Sony both above (A7iii) and below (A6000 in a Nauticam housing) the water. For my A7iii, I am trying (budget permitting) to buy only "good glass" for it. That means staying away from lenses that do not fall into at least their "Prosumer" level. I bought the camera with a kit lens and plan to replace it someday. Virtually all of the lenses that I have bought for it since are either Sony/Zeiss, or Sony G series lenses. (I am currently waiting on a new zoom lens - the Sony 200-600 f5.6-6.3 G OSS)

I think you are on the right track when you say "It's the combo of the lens and the dome/port that matters.", but I don't entirely agree. A superb port will never compensate for a lens that is a poor quality lens. It will never make a lens that is simply not capable of sharp images suddenly produce them. On the other hand, a garbage port does have the potential to make it impossible to get good images from even the sharpest lens.

Personally, I do not think that you will ever regret buying a good quality lens. If you shoot Canon, think in terms of their "L Series", if you shoot Sony, think in terms of their Sony/Zeiss lenses, or their "G" or "G Master" lenses. I'm sorry, but it has been far to long since I have shot Nikon to know what their equivalent lens series is. If you want to save a little money, the Sigma "Art Series" lenses are very good. I would tend to put a higher priority of image quality and (especially underwater) focus speed than I would on maximum aperture. Like I said, for years, my favorite lens was an f4.

As always, please take my post as advice and my personal opinion, and not as a definitive statement of fact.

 

[PatW]

I currently shoot with 4 Nikon lenses underwater. Three of these lenses enjoy excellent reputations: micro f 1.8 60 mm, micro f 1.8 105 mm, f 4 16-35. The other lens is an f 3.5-5.6 24-85. It could be called a full frame kit lens. As far as I know, my housing does not support a more “pro” level lens. But it takes pretty good shots especially if they are not pushing the wide limit on focal length. My wide zoom takes better shots in its range but it has a limited range of zoom. So it is a trade off. Do I go with flexibility or do I go for special situation type quality?

 

[stuartv]

I think you are on the right track when you say "It's the combo of the lens and the dome/port that matters.", but I don't entirely agree. A superb port will never compensate for a lens that is a poor quality lens. It will never make a lens that is simply not capable of sharp images suddenly produce them.

That begs the question: In your opinion, do any of The Majors (Socanikon) make a kit lens for their high-end FF cameras that is poor quality? In other words, wouldn't I be safe with the kit lens and a good dome/port for any of those high-end cameras?

Again, this is somewhat academic for me. I'm not going to invest in any new glass for my existing camera.

I am planning to buy a Sony a7r Mk IV sometime in the next few months. My long-term goal is to use the "kit" lens and get a WACP for it. In the more near-term, I already have a WWL-1 and my research suggests that I can use that with the FF Sony if I get their 28mm prime lens (IIRC). So, that is what I currently anticipate doing. It will be sort of a one-trick pony, but that is the one trick that I particularly interested in.

Asking my original question was not so much about exactly what I should do with my near-term purchases. It was more about educating myself. I have often wondered, hypothetically, if I always shoot at 28mm and f/8 - f/11, is there a reason to buy a "better" lens, or is the "cheap" lens that will do those settings going to work just the same? And now I understand that the answer is "it depends" because the wrong port/dome could make the better lens perform worse overall. It's the combo - the whole package - that must be evaluated.