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06-26-2018, 03:03 PM   #1
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Old Ideas?

Hi all, and as this is only my second post to the forum, I'll state right up that I'm an old film camera enthusiast, who just got back into the photographic world by way of the K1mii mated with a D-FA 28-105 wr. So I am having to re-learn pretty much everything, because I dropped out in the late 90's, and even then, my capabilities were pretty basic.

Anyway, on to my point. So as a primer to get back into the great new digital age i which we find ourselves, I picked up a copy of Bryan Peterson's classic "Understanding Exposure", (great book, btw) and what has stuck me is this:

I have been shopping for lens, and I notice in allot, and i mean allot of descriptions of the lens I'm shopping, and in allot of this forum's wonderful lens database user reviews, it seems that the many folk kind of put allot of emphasis on the lens base F stop, and then speak in terms of it's capabilities from there, in what I may be totally misunderstanding, but I see terms being used like "I have to stop it down from there" in what seems like, to me, a light that paints that as being a less than good thing? To compound my confusion, after about 50-60 pages of reading into Mr. Peterson's book, he just comes right out an states that the idea of wide opens lens is kind of a misnomer, and that any good photographer knows that using small apertures is actually a good thing...I think he even comes right out and infers, get used to shooting (as an exercise) at f/22 (in fact he actually says the idea we should be shooting primarily as large as possible is a dated presumption).

So I realize fully that all things are relative, especially in terms of all the variables involved (obviously, "millions") but if I had not picked up Mr. Peterson's book, I can tell you right now that I would be chasing lens, and making purchases based on the presumption that a lens with a big ol aperture, and it's ability to capture great photos wide open, would have been a main consideration in making that purchase. So should I be putting so much weight on whether or not a lens has bigger aperture capabilities, or?

Any perspectives on this topic would be greatly appreciated.

Thank you all, and I am really looking forward to becoming a full fledged Pentax user, and learning much from this generous group.

My Best,


06-26-2018, 03:24 PM   #2
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wide aperture less depth of field, small aperture more depth of field, lenses have a sweet spot usually somewhere in the middle, lenses are made with different capabilities some are poor to great wide open, all are usually better at the sweet spot in terms of sharpness across the frame, and there are draw backs, softness, (just not thinking of the technical term at present) from using f22 or more. It just depends on your usage, low light might need faster lenses to produce what you want. Lenses render differently some render scenes a long way away really well, some are better at closer distances, some render colour and contrast really well, some do differently.
The D FA 28 - 105 I guess and say an all rounder type lens and would be a great fit to the K-1 II.
just a matter of choosing the lens with the characteristics you need for your photography. There is more others may help with their thoughts as well.
06-26-2018, 03:29 PM   #3
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Thank You beachgardener.
06-26-2018, 03:53 PM   #4
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I think the primary reason folks look for lenses based on base f-stop is the ability to use in lower light settings without flash and without an ISO so high noise becomes an issue. Since just about every lens isn't limited to only wide open stops, the ability to use in bright light is inherent, though focus and chromatic aberration can be issues in brighter light even stopped down, and are generally addressed in coatings, lens design, and glass quality.

Bottom line, if you had two identical lenses only differing in largest aperture available in the lens, generally speaking, the lens with the largest aperture available would be more versatile, in terms of ambient lighting use.

06-26-2018, 04:00 PM - 1 Like   #5
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It all really depends on your use at the time. Put me in a church shooting weddings, and I like my lenses to be f/2.8 or faster. Out shooting a landscape, I want a lens that is quality from f/8 to f/16 or 22.
06-26-2018, 04:49 PM   #6
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Hi @BillyCooper, welcome here.

Earlier forum members already sum up pretty well there. It really depends on what you are trying to take.
For example me.. I like and I shoot 99% urban landscape at night, so I buy lenses based on its sharpness and starburst effect. A lens with a large aperture, well perform wide-open and beautiful out of focus area are a good to have but not a must if it too expensive. I value starburst effect way-way more than creamy out of focus area. If you like to do portrait or anything require creamy out of focus area, you might want to look at something totally different from me.

So “I think”, don’t buy lenses because it perform well at f22 or because it has the largest aperture and a review said it perform well wide open.etc
Ask yourself what kind of images you want first. Then find a lens that can deliver the best result for that particular effect you want.
And keep in mind, there is no such magical lens can do well at everything.

By the way, even I upset with sharpness when doing night urban landscape, and knowing smaller aperture setting can give good-looking starburst effect, I don’t remember I ever use f22 even on a tripod at night. I test and pixel peeping at all of my lenses to find out its sweet spot. Most of my lenses produce best image quality from f8 to f11 (no surprise here). Some lenses doing better at f4 (but I will loose nice looking starbursts). Then I can see decreases in overall image quality when go smaller than f16 and onward. (Again no surprise here too.) f22 definitely gives me less of everything when compared with let say f8 to f11. So another point is make sure you know where is the sweet-spot on your lense and happy shooting.
06-26-2018, 04:57 PM - 4 Likes   #7
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There are at least five reasons for this kind of talk about brighter apertures.

1. Subject Isolation: There's a style of photography that prizes wide-open large apertures to create very thin depth of field and intentionally blurry foregrounds and backgrounds. A cynic might say that these one-eye-in-focus images are created to one-up other photographers who don't have f/1.4 lenses on full-frame cameras. But that's a bit harsh. Done well, the resulting subject isolation can create a very compelling image.

2. Larger Bokeh: A wider wide-open aperture also enables larger bokeh which can also be attractive.

3. Dim Lighting: The buyers who fall into the trap of picking the two most popular camera brands are often often forced to buy big-aperture lenses to cope with dim lighting conditions. With a Pentax camera, especially a K1ii, the use of it's SR image stabilization and excellent high-ISO performance creates much more latitude to pick a reasonable aperture and either slow the shutter or up the ISO.

4. Lens Sharpness: Some of the negative comments saying "I have to stop it down from there" might reflect the need to stop down the lens to achieve better sharpness. Most lenses have worse resolution and more image aberrations when used wide-open. Digital photography seems to encourage pixel peeping usually to the detriment of actually photography. Lens buyers who magnify their first image taken with their new, expensive, large aperture lens only to find some smearing in the corners of the image do complain about it.

5. Diffraction: Digital pixel peeping also means that many photographers avoid anything smaller than about f/11. Although f/22 has the potential to greatly increase the amount of subject matter in focus, all of that in-focus material will have a noticeable fuzziness due to diffraction. But maybe a little diffraction is fine if serves the greater purpose of a deep landscape image with foreground flowers and background mountain vistas.

Overall, I'd say that every aperture is useful for something although the ones at the two ends of the spectrum come with serious trade-offs. I'd also say that every aperture is wrong under some circumstances. Even the so-called sweet-spot aperture is wrong if it has either too much or too little depth of field, if it prevents using a very slow or very fast shutter speed, or if it forces too high an ISO. Ultimately, a faster lens does add a niche of photographic options as long as the photographer is willing to put up with the size and weight of the lens. It's up to each photographer to decide if they really want those options for super thin DoF, big bokeh, extra light gathering, etc. A proverbial 99% of images do not need big apertures so they are really aren't needed to be a great photographer. But some do enjoy that 1% niche.

Have fun with your K-1ii and welcome to the forums!
06-26-2018, 05:34 PM - 1 Like   #8
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I have a similar story, having dallied with film cameras back in the 80s & 90s, and then making do with a couple of point and shoot cameras (Pentax and Ricoh as it happens) until buying a used K5 a little over a year ago. While I started out with every intention of buying only new and well rated lenses I've become happily distracted with older lenses. This has been fairly economical, and without the expense and time involved in having film developed and prints made, allowed me to learn much faster than I did with film. As a garden variety amateur, and relative newcomer to digital I think it's good to be able to match the qualities of a lens across all apertures to the pictures you take, and can tell you how I've found the open aperture qualities of the lenses I've bought useful to date.

I think there will always be a certain cachet with having the biggest, or in this case, fastest or sharpest, model of anything, but the general characteristics of many lenses wide open do have their uses, and having good performance at wider apertures does also have it's advantages, however it's defined. I have so far been mostly photographing flowers and insects around the garden, and also views around the township where I live, with the odd street shot, landscape and architecture, and cat portrait thrown in. The ability to use a narrower depth of field wide open to selectively focus on things close up has been great, but more recently I've also found that the ability to give adequate detail and sharpness wide open while retaining some softness is also useful. This is generally recognised in portraiture, but I'm also finding it good for getting a soft feel to the petals of flowers that a sharper rendering won't. In the last month or so I've also found a processing feature that subtly removes fine detail, and I've found this useful once or twice in simplifying a picture so the basic elements that attracted me to that shot are more accessible and easily apprehended to those viewing it. Looking at pictures online I also wonder if some people get carried away with the "Gee whiz!" aspect of the selective, or partial, focus they can achieve with faster lenses at the minimum focus distance, and have found that lenses considered too soft to use wide open actually give sharper images (and better depth of field) if I step back a bit (obvious when you think about it, but.... took me a while ). Of course it's also good to be able to take photos indoors or in low light situations, overcast or pre- or post-dawn, without using a flash or pumping up the ISO and noise. It's also good to be able to get a sharp and detailed photo of a landscape or tree or building, or for a professional a product maybe, when stopped down. If you intend on doing this in low light or very selectively then a lens that is sharp wide open would make sense. Otherwise some softness wide open may also have it's uses.

Another point worth considering when looking at these faster lenses is how usable the wide open aperture will be with such a narrow depth of field, and how this balances with the style and subject of the photograph. I'm finding that I can reasonably use f1.7 and f2 (with the Pentax magnifying eyepiece and an aftermarket focusing screen) and so far these apertures are fitting the narrowest, so to speak, of my requirements. Looking at pics online I don't know if I could use f1.4 or f1.2, or if I need to or if it would be worth the trouble trying. Some people say it is, some say it isn't. Probably looking at the pics (there are several f1.2 threads on the forums here, at least Pentax & Cosina if I remember rightly) will give you some idea of how this will suit you. Some folk also say these lenses are sharper, but for my purposes I think it'd be splitting hairs to argue the point.

Learning to use these open apertures in a way I never did when I used film has certainly helped me achieve what I originally set out to do - document what I was seeing in the garden every day - but I am also now beginning to broaden my ambit, and actively look for photo opportunities elsewhere that need more detail, and there's more learning that comes with that. While I may eventually need sharper optics and better coatings, I'll also be happier having another look at the kit lens (18-55) again when I do try autofocus again. I guess what I'll be trying to do is find a balance between the speed and other lens qualities for everyday use, and know which lens will best do the job for more specific purposes.

And then there's always so much more to learn, and I'd be sorry if I ever got to the point where I stopped learning....

Last edited by rjbrett; 06-26-2018 at 09:52 PM.
06-26-2018, 05:39 PM - 1 Like   #9
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I attended a presentation by this professional wildlife photographer last week. She is average size and strength, yet she lugs a 500mm f/4 lens around to get shots like this:

Sandra Lee Photography | Dakotas

The backgrounds are very important to her (you may want to browse her other shots). Her Canon Digital Pro body is nearly 10 years old (Iím not kidding) but she (appropriately) insists on the fastest (widest aperture) lenses for most of her shots - a 300/2.8 and the aforementioned 500/4.

While there are photographic situations where you can take fantastic pictures with older, slower, inexpensive Pentax lenses (and you can learn about them on this forum), there are very good reasons pros want wide-aperture lenses.

You just purchased an excellent lens and camera - I suggest you take full advantage of it. I also suggest you pick up a reasonably priced 100 or 135mm lens (such as the f/2.8 models - used is fine) and see what it does for you. This experience should answer most of your questions.

You may also want to browse the Pentax Photo Gallery, selecting different lenses, and see what appeals to you. Most photos include information on the lens and camera settings used.

PENTAX : Welcome to the PENTAX Photo Gallery
06-26-2018, 10:41 PM   #10
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QuoteOriginally posted by BillyCooper Quote
So as a primer to get back into the great new digital age i which we find ourselves, I picked up a copy of Bryan Peterson's classic "Understanding Exposure", (great book, btw)
Not much I can add to this conversation that hasn't already been said better than I could ever say it. But I wanted say that what you did in film photography, applies for the most part to digital. And I agree 100% with you, Brian Peterson's "Understanding Exposure" is an excellent primer for getting into, or back into photography.

And most importantly, welcome to the Pentax Forum. This is an amazing resource and community that I am proud to be a part of.
06-27-2018, 12:16 AM - 1 Like   #11
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One small add that I didn't notice before on skimming through - though apologies if the point has already been made - is that faster lenses give a brighter viewfinder image if you're using the viewfinder. This helps to see the subject in darker situations - and also allows AF to work through quite heavy ND filters in brighter situations. Also, as has been suggested, faster lenses are necessarily more expensive as (with a few Ltd exceptions) they tend to have more and larger glass - but as they already price themselves out of the consumer grade, they tend to be of better optical and mechanical quality. Of course what's fast depends in real world situations on the focal length - you wouldn't be able to lift a 600mm f/1.4
06-27-2018, 12:23 AM - 1 Like   #12
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It's all been said, apart from the Big Boy Toy crowd, who NEED the latest F0.75 lens, because they can
Personally I only go to F1.7 (AF) or F2 (MF), there's next to no difference between exposures at these apertures. I like my Pentax-F 1.7 in terms of IQ and the speed sometimes helps, however I rarely use 50mm on DSLR, it's an odd length for me not being a portrait taker. The "slow" F2.8 40mm however...............
But I mainly shoot wildlife and as the lottery hasn't chosen me yet, shooting at anything north of about F6.7 is a pipe dream. Because that's telephoto, I can get all the subject isolation and blurry backgrounds I need.

As I find over and over again with this hobby, it's horses for courses. Pick the lens & body for the job, not the badge.
06-27-2018, 12:48 AM   #13
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The others before me have already given you complete answers.
So welcome to the forums, and I'm sure you'll get the hang of all trade-offs (softness-sharpness-diffraction, more light-less light, less DoF-more DoF) in no time.
06-27-2018, 08:16 AM - 1 Like   #14
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What aperture setting you use really depends on what effect you want your photos to have.

A small aperture will produce a large depth of field, i.e. foreground and background will be sharp. This is good for landscapes. A wide aperture will produce a shallow depth of field, i.e. only the selected focal point will be sharp and the foreground and background will be out of focus. This is good for portraits.

Aperture, shutter speed and ISO are all linked and it's a matter of trading off between them until you find an exposure setup that works best for what you're after. There's no right or wrong settings to use which is why photography is creative!
06-27-2018, 08:30 AM - 2 Likes   #15
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One other consideration: the "glow" that happens in most fast lenses wide open. It is very flattering in portraiture, and can seem to be almost magical at times for other types of subjects.

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