Wide Angle Lenses - How to choose, How to use

Topic

Interested in wide angle photography?  This article walks though how to use a wide angle lens and how to shop for one.

What is a wide angle lens?  Let's literally take a look:

In the photo above, the outer blue box shows the view from a wide angle lens (a 15 mm full-frame equivalent with a 110 degree field-of-view).

The inner blue box shows the framing you would see from a typical cell phone camera if you were standing in the same spot. (40 mm equivalent with a 56 degree field-of-view)

With this example cell phone, you could back up to get more rocks and shore but this is not going to give you the same image as the wide angle.  For starters, the distant shoreline won't change much in size when you move back, making it much larger in the 40 mm than it currently is in the 15 mm version.  Essentially, the relative sizes of all near and far objects will be less different with the longer lens.

Thus the only way to get the same wide angle image with our example phone camera would be to do a panoramic stitch.

Uses

The main uses for a wide angle lens are:

Landscape

Canon Beach - taken with a 15mm lens (APS-C) with an 88 degree FOV

As shown above, a wide angle lens can capture more of the overall landscape scene in a single image and thus provide a "different" look than what most people can achieve with their phones or travel cameras (unless they do a panoramic shot and these don't always work out well).

Interior

Wide angle lenses give interiors a feeling of "spaciousness" (15mm image shown)

Wide angle lenses also make car interiors look larger, as this 11 mm image shows.

Real-estate photographers usually opt for wide angle lenses when photographing interiors because the exaggerated perspective creates a feeling of spaciousness - making rooms appear larger in photos than they will in person.  Car interior photos are often wide angle for the same reason.

Architecture

A wide angle lens was used here to help show the scale and complexity this old railroad avalanche shelter

Architecture photos often use wide angle lenses, both for practical reasons (limitations on where the camera can be placed with a clear view), and because wide angle lenses give more options for cropping.  Cropping (or shifting) is needed when the photographer wishes to avoid keystoning effects.

An example of "keystoning" where angling the camera causes parallel lines to angle toward one another.  If this is not the desired effect, shooting the scene with a "leveled" camera, then post-cropping is one strategy.  Using a wide angle lens can help.

Less Popular Uses

To start, I'll say you can attempt to use any lens for any purpose but the following uses "go against the grain" and thus enter the realm of creativity.

• Close Portraits: To get a person to "fill the frame" with a wide angle lens, you have to get the camera very close.  This creates personal space challenges which can make many people less comfortable.  The other potential problem is that the resulting image will reflect the close perspective, rendering a larger nose, smaller ears, and a unusually-shaped head.  Although this can be a fun way to be creative, people usually prefer traditional methods.
• Macro or Product:  It's quite common for a wide-angle lens to be able to focus very closely, even an inch away from the front of the lens.  Outside of exaggerated perspective, the issue here is the effect of the camera lens on lighting - the lens can actually block useful light from reaching the subject!

Issues, With "Work Arounds"

Wide angle lenses are a challenge to use well and come with many inherent compromises.  This section attempts to cover the major ones.

Distracting Elements In The Frame

Because wide angle lenses capture so much in a single image, it can be a challenge to keep distracting elements out.  This can especially be difficult when starting out under a "single subject" compositional mindset.

My advice here is to shift compositional thinking to "whole image".  This means first looking for a favorable wide-angle environment, then looking for specific subjects after that.  I highlight some specific examples below:

A beautiful sky is a nice time to go with a wide angle lens.  The sky can cover a good portion of the frame in a complimentary way.  Water is another good compositional component for the same reason.

Oftentimes, the sky is not interesting enough to deserve space in the frame.  In this case, consider minimizing it in favor of more landscape elements.

Large areas of a given pattern can work well to simply an image and avoid distracting elements.

Finding A Subject

If your photo is built on a singular subject, you'll often have to get close to that subject or it will be too small to "stand out".  Some tips for doing this are shown in the images below.

Getting the camera very low to the ground allows small objects to be used as a subject

Another option is to allow the subject to be small and build the composition to embrace this smallness

With natural subjects, such as trees, it's often possible to get very close without the resulting perspective distortion becoming bothersome.  This image was taken with a 10mm fisheye lens at a very close distance.

Subject Background Balancing

Background objects taken with a wide angle lens become very small, almost too small to be a part of the photo.  Because of this, distant features such as mountains should mostly be considered an "inconsequential" part of the composition.  Foreground objects and sweeping objects (sky, landscape) need to mostly carry the image.

An image of Mt Rainier with a 100 mm lens.  Long lenses make it easier to include background elements, although this feature can bring  with it a sense of two-dimensional "flatness" to the image. 

An image captured from the same shoreline with a 15mm lens.  See how Mount Rainier in the distance (left of center) has become nearly irrelevant to the composition?  Anything not close up or vast in wide-angle tends to become marginalized.

Distortion

It took me a while to realize this, but distortion can mean a combination of several separate issues:

• Lens distortion:  This is a tendency for lenses to make straight lines look curved.  On some wide angle lenses, it's complex where lines in certain dimensions (say parallel to the frame) are straight where others (say toward the camera) have a curve.
• Perspective distortion:  This is a natural distortion where objects that are actually to the side of the camera suddenly have to be projected onto a flat rectangle.  The result is strange-looking bending and warping near the edges of the frame.
• Keystoning:  Oftentimes the effort of getting a good composition means tilting the camera up or down.  This action causes straight lines to bend toward or away from the frame.  The keystoning effect is not limited to wide angles but tend to be exaggerated by them.

Some examples:

Note the severe unnatural bend of the boat masts on the right.  This is a combination of perspective distortion and keystoning (angling the camera upward)

Another example, where boat masts become progressively more angled to the right of the fame

One workaround for these problems is to simply go a little less wide as the issue becomes increasingly harder to keep under control as you go wider.

Another is to try and place objects without obvious proportions nearer to the frame edges.  Natural objects like water, rocks and trees tend to work well.  Man-made objects like buildings and signs make it more obvious that something is "off".

A third method is to try and keep the camera level to minimize the effect, perhaps with some post cropping after-the-fact.  This is a trade-off that you'll have to apply your artistic discretion toward.

Finally, you can simply embrace the effect, even try to exaggerate it - it's all subjective opinion at the end of the day, after all. :)

Field Curvature

Although it's natural to think of a focus plane as a flat plane in space, in reality it's never quite so simple. Wide angle lenses, in particular, have quite a difficult time keeping the focus plane "flat" (to varying degrees).  Also note that this curvature is a part of the design compromises in the lens, swapping copies of the same lens model is a frivolous exercise.

Why does it matter?  Mainly because you need to be careful how you focus.  If you don't then you can expect problems like soft corners that can otherwise be avoided.

To address this issue, you will have to see if and how much it's a problem for your lens.  If it's a problem, you'll have to experiment with what part of the frame you use for focusing.  For my favorite wide-angle, the "recipe" for best overall landscape focus is to focus about 1/4 away from the bottom corner of either frame.

What To Look For

This section talks about things to consider when purchasing a wide angle lens. 

Flare Can Be A Problem

By their nature, wide angle lenses capture light from many angles.  Designing a lens that keeps flare low in these situations is a challenge that many lenses (even expensive ones) don't meet too well.  To make matters worse, lens hoods often have to be sparse to prevent vignetting issues.

The best way to determine if a lens has too much flare is to rent or borrow it and decide for yourself.  You can also check a review site like lenstip.  Finally, you can visit a "samples" site like pixelpeeper or flickriver.  On these sites, you can choose the lens you are interested in and check out images with the sun or bright lights.

Don't Forget About Filter Support

Filters are quite useful in landscape photography.  ND filters can allow for long shutter speeds, showing the flow of things like leaves and water.  Polarizing filters can reduce glare on objects, improving color and clarity.  Even color filters are still useful in digital if you are using advanced techniques (like RGB channel balancing with ETTR).  We won't cover details in this article...

The issue I'm getting to here is that many wide-angle lens designs use a "bulb shaped" front element.  This design can improve sharpness but filters are difficult and often expensive to mount, requiring creative after-market approaches.

The Nikon 14-24mm is a lens of legendary sharpness.  Unfortunately it's flare resistance is only "OK" and adding filters to the bulb-shaped element requires expensive after-market workarounds.

The Pentax 15 mm contrasts the Nikon 12-24mm in nearly every respect.  Image sharpness is good, but not "legendary".  Then again, the flare resistance is excellent and inexpensive 49 mm filters can be easily attached.

Note that polarizers don't work too well on very wide angle lenses of any type due to the extreme light angles.  This leads to vignetting on the edges of the frame.  For moderate wide angle lenses, they are fine.

Good Manual Focus > Auto Focus

At least for most people.  The reason is that the depth of field is so large on wide angle lenses that zone focusing is effective.

This Sigma 10-20 has a "high speed internal motor".  I prefer a great manual focusing experience for this type of lens.

The Zeiss 21mm is $1800 and is manual focus only.  It's a very nice manual focus too...  Too bad the lens flares a bit too much.

Another reason is that, due to field curvature, you'll probably want to focus using magnified live view.  Manual focusing benefits from a long focus throw which autofocus lenses generally do not have, making live view focusing more precise.

For the reasons above, many of the most expensive wide angle lenses are manual focus only.

Focus Scales Are Nice

A lens with focus scales is nice with wide angle because you can "learn" what scale positions work well for certain shots.  This can save time and also provides a sense of confirmation that things are setup correctly.

No focus scales on the Sony 16-35mm.  This means there is no way to zone focus the lens and you'll have to do your best with the LCD.

Weather Sealing Is Nice

Although uncommon in less-expensive lenses, weather sealing is a nice feature in any lens intended to be used in outdoor landscapes

Weather sealed with focus scales and filter support.  A strong contender :)

Wide Angle Zooms Can Be Tough To Master

Basically, all wide angle lenses have their "quirks" like field curvature, flare, etc that you have to learn to predict and work around.  With a zoom lens, these quirks often vary by focal length, making it even harder to pre-visualize your results.

The complexity of zooms might also make decentering a higher risk as there is simply more that can go wrong.

I also found that it's not always obvious which wide angle focal length to pick.  For these reasons, I have gravitated to primes when using wide angles.

Software Stitching Can Emulate Wide Angle - Sort Of

In modern times, you can also put your camera (with a regular lens) on a tripod (or even handheld) and photography many images in a grid.  You can then use a tool like Hugin or Microsofts Image Composite Editor to stitch them together - and both tools are free!

The downside is that making a wide angle image this way is a lot more work.  Another problem is that movement in the frame can create big problems, even ruin an attempt completely.

Summary

Wide angle lenses can be a real asset and are quite a bit of fun to use.  That said, they are specialty lenses and often bring more problems than benefits in a "typical" photography scenario.

If you are interested in wide angle, my advice would be to rent before you buy and get a feel for what it's like to use such a lens.  I'd try a few from primes to zooms, even a fish eye, and simply see if it's something you enjoy.  Have fun!

Creativity

I feel that I've written enough technical articles in the past couple months and now it's time to talk about something more important: creativity.

Photographers often discuss what makes a photo a "good photo", referring to composition, level horizons, etc.

To me, a factor that really makes a image stand out is when it has a sense of uniqueness.  A second factor is when every aspect of the photo comes together in a unified way, usually as a message or just a pure emotion.  Photos that can do both of these things tend to be special and very difficult to create.

Let's focus on the first aspect in terms of creativity.

This article shares a bit of my personal story of creativity.  It includes images I have taken over the years that I consider creative efforts, including some that I have never shared due to thinking they were "not good enough".  Thus, I'm not implying that creative efforts alone make these photos "good", but I am stating that they helped me tremendously in my personal growth.

2012 was my first year of "creative photography" via a 365 project.  I think it led to images that are not "technically superb", yet still have an enduring quality that outlast their technically superior peers I captured at that time.

The goal of this article is to inspire you to prioritize creativity and to give suggestions on how to nurture it.

Maybe this article is not limited to photography...

The Birth of Creativity

Creativity comes from the marriage of an idea that feels novel and the motivation to explore the idea.

Using bokeh to simulate a spectrum

Creativity never guarantees a remarkable result.  Perhaps the idea felt novel, but is actually common.  Perhaps motivation can not cover for the lack of skill, knowledge and luck needed for a good result.

But remarkable results are, by definition, not easy.  If they were, then everyone could easily achieve them and they would thus lose their quality of being remarkable.

Whether you are running a race, competing for a job or trying to excel at an art, the game is always the same: put in the work that unlocks your natural potential and try to overcome the inevitable series of setbacks and obstacles that come naturally with progression.

Thus creativity should not be thought of as a "shortcut" to success but as a building block toward a goal and ultimately a vision (more on that in a future article, perhaps).  Many attempts at creativity will feel like failures as they tread on unfamiliar ground. This feeling of failure can push a person toward past "safe successes" but these failures should be viewed as valuable opportunities for education and improvement.

During this shoot, I noted the "fiery effect" of the first image, then changed settings outside of my normal comfort zone to make it more pronounced.  I then tried different tones, eventually feeling that red treatment was a bit too blunt.

Success and failure are two sides of a double-edged sword.  One provides natural feelings of motivation but little in terms of learning potential.  The other does quite the opposite.  I believe you need a balance both to keep moving forward.  Success motivates, failure teaches.

This image is a "refined by experience" version of others that I have shared before.  I feel "safe" with the share and can predict the reaction but there is little opportunity in terms of personal growth.

Nurturing Creativity

Make it a Priority

To nurture creativity, you need to first give it priority.  A quick test:

• Look at your last 25 different photos (e.g. not duplicates of the same thing)
• How many gave you a feeling that you were pushing a personal boundary and were not sure how or if they would work out?
• If the number is less than 5, maybe more priority is needed...

by the way: my own test of this experiment (in March, 2016) shows that I need to give creativity more priority - I'm playing it too safe right now...

Force Discomfort

"Forcing Discomfort" means creating an environment where it's hard to take the photos that are in your comfort zone - spiritual duplicates of photos you have taken many times before.  Here are some examples:

• Do you depend on amazing lighting conditions?  Try going out in the middle of the day or during overcast conditions.
• Are you a master of subject isolation with depth of field?  Try using only your mobile phone.
• Do you post process every image in Photoshop or Lightroom?  Set your camera to JPEG mode and try some of the creative filters.
• Do you always crop?  Try to go a month without ever cropping a photo.
• Do you never crop?  Try to go a month cropping every photo to a 1:1 square or other ratio.
• ... and so on

I very rarely shoot with a long lens and this is one of only five images I captured in 2015 using one.  Perhaps the difference is what led me to "see" the potential of framing this the image with an intent to vertically "flip it", thus creating a near-subconscious source of tension and interest.

I don't recommend changing too much though.  I think that changing too much at once can give a "fish out of water" feeling that is not productive.  Instead, I recommend forcing only one or two differences and keeping the rest in your comfort zone.  This should encourage exploration and discovery along that new path.

This image of falling Jenga blocks was a challenge to capture in that it combines a blurring ambient exposure with a motion-freezing "flash".  From an external perspective "it's been done" but I had feeling of creative motivation during the process and this pushed my knowledge forward.

Also note that the goal here is not to find an easy path to amazing images, quite the opposite is likely.  Instead the goal is to gain knowledge and spark ideas.

Apply Vision

Vision in terms of a single image is the concept of "seeing" a photo in your mind months or years before you capture it.  You set the stage in your imagination, perhaps while listening to interesting music or in a special place of reflection.

What follows is a series of "attempts", each of which captures part of, but not all of the vision.  Some lucky visions might truly be found, and these images will be special.

My advice is to do what it take to personally get your creative thinking engaged (visiting a favorite quiet place, etc), and coming up with "idealistic" ideas that can then be chased and hopefully achieved.

My "first opportunity" of a photo vision I had for about a year before finding the image.

My "second" opportunity of the same vision, taken a year later.  It's still only about 70% there.  I hope to have another opportunity in the future that gets even closer...

Flash Cards

Here is an idea that I sometimes use.  Get some flash cards and write down idea fragments - one per card.  My personal cards look something like this (one per card)

• ND Filter
• Flower
• Long Exposure
• Fill Flash
• Macro
• Zoom blur
• Light Painting
• Tree
• Infrared
• Dancer
• ... and so on

I wouldn't worry about rules in making your cards - rules are the enemy of creativity after all.

Flower + Vignette + Zoom Blur

After you have enough, shuffle and draw three.  Think about various combinations of the three cards.  Any ideas?  Write them down to think more on later.  Try a few times and see how it goes!

More Thoughts?

If you have thoughts or tips on creativity you would like to share, I'd love to hear them below!

Choosing A Tripod

Choosing A Tripod

When staring photography, one point of confusion is often which tripod to choose.  I have some unfortunate news for you, if the tripod you choose is used often, it will likely be inadequate.

Why?  Because tripods are an endless list of compromises and the "best" compromise is going to depend on the photographic situation at hand.  When starting out, favorite subjects are often undecided and tend to evolve with the photographer.

As tripods compromise some qualities for others, often it's the case that multiple tripods best fill varying needs.  At the moment, I have five tripods, all of which are "best" at different things.

This article briefly explains why you need a tripod at all, then looks at different tripod features and which styles they cater to.

Cheaper tripods come included with heads while more expensive ones require you to purchase a head separately.  Tripod heads have their own set of trade-offs; I opted not to cover them in this article.  If you are looking for a quick head suggestion, many people like ball heads with Arca Swiss style plates.

Why a Tripod?

A tripod holds your camera for you and is able to do so with more stability that you will be able to manage without one.  This gives you many advantages for photographs where the scene is static enough to allow for careful positioning.  Some advantages include:

• You can take the time to tune the composition.  This means checking edges of the frame and considering if a different perspective would be better
• In many cases, a tripod makes shutter speed a free variable.  This allows you to shoot with optimal ISO and aperture settings to maximize image quality.
• If you would like to shoot HDR or focus stack, a tripod will keep the camera in a static position between shots
• You have the option to do really long exposures, keeping the shutter open for several minutes, or more!  The resulting photos can be quite exciting.
• A tripod lets you try several back-to-back shots with only one parameter changed.  For example, if you are not sure which aperture setting you want for a photo, you can try a few different ones while keeping the framing fixed.

I would say that if you shoot primarily landscape or still-life macro, then a tripod is a huge asset.  Shooting moving things tends to make a tripod less useful.

What about image stabilization?

Many cameras provide image stabilization features.  Image stabilization basically works like an unreliable tripod "on demand".  Unlike a tripod:

   - You can't 100% rely on image stabilization
   - You can't take identical shots back-to-back

   - You can't do longer exposures

That said, when taking a tripod is not possible or highly inconvenient, image stabilization can "bridge the gap".  Another nice thing about image stabilization is that there is no setup required, which makes image stabilization convenient for dynamic situations, like wildlife.

Tripod Attributes

This section talks about attributes that all tripods have.

Material

Left-to-right: Aluminum, Carbon Fiber, and Steel

The main materials you'll find for tripod legs are aluminum and carbon fiber.  It's also possible to find steel, wood, plastic, and various other materials.

Between aluminum and carbon fiber, carbon fiber has a slight edge in weight and stiffness.  Carbon fiber also generally costs 2-3 times more for the same model.

If you are going for pixel-perfect images, you might also consider that some materials are more prone to vibration from shutters and mirrors.  I'm not an expert here, but know that materials like carbon fiber and wood tend to dampen vibrations a little better than aluminum.  This will mostly be a concern when using very long lenses or with macro work.

Outside of the legs, there are also the joints locking mechanisms which vary in quality.  As you'd expect, there is a correlation between higher quality materials and price.

Weight & Bulk

Due to varying materials and leg section counts, tripod weight and bulk are separate consideration

How much the tripod weighs mainly affects how nice it is to carry.

Intuitively, you might also think that more weight means more stability.

While this intuition is correct, it overlooks the fact that tripods with hanging hooks allow to you make them almost arbitrarily heavy.  I often use my camera bag to do just that.  Thus leg stiffness can actually make a bigger practical difference than carrying weight.

Separate from weight is bulk.  A bulky tripod may not be easy to attach to a smaller bag, even if it's lightweight.  I actually have this very situation where my lightest carbon fiber tripod can't really be used as my "everyday traveling tripod" simply because it's too bulky to fit on my bag.

Leg Section Count

Four leg sections verses three.

Fewer leg sections lead to an inherently stiffer tripod but also one that has more "bulk" than one with more sections.  Basically, each leg joint serves as a point where additional flex can occur.  Money can partially fix this with stiff carbon fiber and higher-end joints but nothing quite matches the stability of no joint at all.

Maximum Height

Center post extended (taller) and not extended (shorter).

The trade-offs of bulk vs leg section count combine to determine a tripod's maximum height (without the center column extended).  Said another way:

• With fewer leg sections, you'll have either a bulkier tripod or a shorter maximum height.
• More leg sections allow for more height, but compromise relative stiffness

Beyond the maximum leg height, additional height can be achieved via an extending center column.  Extending this column compromises tripod stability by raising the center of gravity.  If setting up in windy conditions, you'll want to take care with a high center of gravity or your equipment might take a tumble.

Minimum Height

Two ways to get the camera low, each with it's own trade-offs.

The minimum height of different tripods varies.  The main factor here seems to be cost and complexity.  Simply not allowing a height lower than the center column length keeps things cheap and simple.

Many photography applications have little need for low heights.  If you shoot landscape or macro, however, you should give this feature consideration as it will allow for those creative "wow" angles that can make a difference in your results.

The mechanisms that tripods use to allow for lower heights are:

• Reversable center column
• Split Center Column
• Extra Center Column
• 90 degree Center Column
• Rotatable Center Column. 

These are all described in the features section later.

Maximum Load

Maximum load is how much weight a tripod says it can carry.  One problem with specifications here is that they are "marketing" numbers and it's hard to know what they are referring to.  In any case, I'd recommend simply making sure you have some margin to work with and read user experience reviews.

Mounting Screw

There are two standards, 1/4-20 (smaller) and 3/8-16 (larger).  The former is generally reserved to smaller tripods that also come with heads.  Most other tripods will use 3/8.  It's possible to convert one to the other quite cheaply with adapters although doing so suggests that the tripod and head are not well-matched in capacity. 

Tripod Features

These sections briefly describe different features that a tripod might have and offer suggestions on why you might care.

Center Column Features

Invertible

An invertible center column allows you to mount the camera under the tripod.  This is a great way to use the tripod as a "copy stand" alternative to scan film or photograph small items from above.

This can also be used for low-to-the ground shots, although the fact that the camera is located in the center of three tripod legs can sometimes hinder camera positioning.  There may also be the inconvenience of having to operate the camera upside-down.

90 Degree Orientation

Creative Potential: Excellent  Stability: Not Excellent

These type of tripods (mainly by Manfroto) allow the center post to be positioned at a 90 degree.  The design of these tripods allows this maneuver to be done quickly.

This position can be useful for macro shooting where the camera legs would otherwise impede the best camera position.  It also allows for nice close-to-the ground shooting with more convenience and fewer compositional limitations than the inversion approach.

Yet another use case is overhead shots where the camera is pointing straight down.

Note that a 90 degree mount is inherently less stable than approaches that keep the camera centered between the legs - you'll need to take care when using it.

Swinging

Some tripod designs allow the center column to be "swung" at a variety of angles, not just 90 degrees.  This is a really flexible feature offering the benefits of 90 degrees and more.  The stability downsides of a 90 degree tripod do not improve here and in fact may be worse.

Splittable

I used to own a splittable center column.  Now I own half of one...

Some tripods have threaded center columns that can be split into two parts.  When the column is separated, the tripod to go much lower but there are drawbacks:

• It's possible to leave the detached center column at the photo site.  I did exactly that with mine.
• There are temperature concerns.  Metal expands and contracts based on temperature.  Screw together your center column outdoors, bring it inside where the temperature is quite different, and now you need tools to get it apart again.

Replaceable

Some tripods are boxed with two center columns -- a long one and a shorter one for low shots.  I think this approach is somewhat inconvenient for most people because keeping track of and switching this extra part is burdensome.  If you have clever logistics in place and don't mind the extra hassle, then it can work out.

Weight Hook

This tripod lets you attach accessories to the bottom post, including hooks for bags or weights

A hook or screw at the bottom of the center column gives you a place to put your camera bag or something else heavy to give the tripod more weight and a lower center of gravity.

The downside is that the hook can make the column more difficult to remove.  The hook location also may be too close to the ground to hang weights in some cases.

Leg Features

Retractable Spikes

Retractable spikes can make a tripod more stable in landscape shooting.  A downside is that the retraction "holes" can readily collect dirt, redepositing it randomly where the tripod is used.

Twist Locks (vs Flip Locks)

Here, I am talking about the lock for tripod leg sections.  Twist locks allow for smoother/quicker motions.  Flip locks leave no question about what the tension should be.  I consider it to be a minor difference, for the most part.

Other Features

Attachable accessories

Some tripods have secondary screw mounts where you can attach a variety of accessories, such as secondary arms.

Apex Hook

Some tripods have a hook where the legs meet (apex).  This can be used to hang weights or your camera bag.

How to Choose

You can go with a special purpose tripod or a "jack or all trades" one.  To decide, simply identify what you will be using the tripod for.  If you are not sure, then you should get a "jack of all trades" one that is moderately priced for your budget.

Use cases and Features

The following section briefly states various use cases and what features (and attributes) are important for each.

Landscape

A landscape photo taken inches from the ground

• Concerns: Carrying weight.  Maximum height.  Minimum height.  Bulk.  
• Advice: This one is tough because many attributes offset one another.  Carrying distance will be a factor.  I recommend not skimping on a tripod for landscape use, go for carbon fiber if you can.

Macro

For this photo, I used the 90 degree arm to get a nice angle

• Concerns: Adaptability.  Minimum height.
• Advice: Another tough situation.  Being able to hold the camera at creative angles (such as with a 90 degree or swing arm) will be helpful for getting a nice angle.  Then again, keeping the camera stable is important too. 

Studio

Taken at home with off-camera soft boxes.  Tripod weight here was a non concern verses stability and versatility

• Concerns: Maximum height.  Stability.
• Advice: I chose this use case because it is so different.  Weight is rarely a concern here with many studios choosing to bolt their tripod (e.g. camera stand) directly to the floor.

Other

The above use cases are just examples, the key point is to think through how you will be using the tripod and choose trade-offs accordingly.  Good luck!