Does aperture priority mode work with a manual aperture lens?

Question

I'm interested to know if there are any limitations when shooting with a manual aperture lens in aperture priority mode, compared to shooting with a fully automatic lens.

In case this isn't clear, the lens has a ring that sets the aperture. There is no wiring to communicate aperture information to the camera, so the camera does not know what the aperture is.

Questions I have when using aperture priority mode:

• Is the camera able to calculate the exposure with this lens?
• Does TTL flash metering work?
• Can I bracket the exposure?

Edit: while I'm interested in general about how cameras support this configuration, I need to have this information for Canon DSLRs, specifically the 60D.

Asked by Miguel

Answer

Aperture priority mode works just fine with a manual lens (or no lens at all) on my Canon 550D so I assume it will work on a 60D

What happens is that the camera display shows an aperture of "F00" and the camera will set the shutter speed based on the amount of light it can see (making the result picture exactly the same as if you set the aperture in the camera).

Note that the viewfinder will be darker than with an electronic lens because it will also use the aperture you set (normally the viewfinder always uses the max aperture and the camera only stops down when you press the shutter or the DOF preview button)

My experience with this is in shooting macro pictures with an hand held reversed lens (from the point of view of the camera no lens at all) and the metering works just as well as it does with a lens attached.

So:

• Can the camera calculate exposure - absolutely yes.

• Does TTL flash metering work - yes, with the same rules as Av mode with a lens (shutter speed will be the same as with no flash, flash used for fill).

• Can I bracket exposure - Yes (just tested it now, never tried to use bracketing with no lens before).

Answered by Nir

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What advantages does manual mode have over aperture priority mode?

Question

I'm wondering what are the most compelling reasons to switch to manual mode on my DSLR. I mostly just use aperture priority mode so I have good control over the depth of field combined with an awareness of the shutter speed that goes with it. My photography is mostly done wandering about with camera in hand, or occasionally on a tripod. I don't do studio photography and I just use the natural light.

I did learn how to take photos manually (with an Olympus OM-1) so I know how to do it, but I enjoy the extra convenience of aperture mode, particularly being able to take the photo quickly and capturing the moment rather than fiddling with dials and missing the shot.

So what would be some key advantages of using manual mode for my sort of photography that are worth the (small amount of) extra hassle involved?

And do you have any tips to minimise the downside (other than practicing to be quick)?

Answer

I typically use aperture priority as well, but I also work a fair bit in manual mode. The typical case for me is if I am in an environment where the lighting situation is quite static, but the subject may have a lot of contrast. Here I switch to manual mode and shoot a few test frames to pinpoint the exposure (typically I try to spot meter on a white surface, and then overexpose that reading by 1.5-2 steps as a first guess).

The main advantage is that you are in full control, and the camera will not be "fooled" by unexpected contrasts in the frame. The downside is that it is a bit slower to change exposure in case the lighting situation changes.

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Why does my Canon 60D sometimes lengthen exposure when using the flash?

Question

In low light conditions, my first shot will often be handheld with no flash. If there's not enough light however, the shutter speed can be too slow and I'm not steady enough for a crisp image - so I'll pop up the flash.

However, I've found that the camera often decreases the shutter speed (i.e. a longer exposure) even though the flash is firing! I mainly find it when shooting in Aperture Priority mode (with ISO on auto).

Why is this? Surely the additional light from the flash would mean a shorter exposure would suffice?

Answer

There are two reasons why a camera might choose to use a slower speed with flash than without:

• it tries to fit exposure into sync speed (1/250s on Canon 60D).
• and/or it chose lower auto ISO thanks to flash usage

Usually, flash is only used to illuminate subject. Your camera still tries to make sure the background will be correctly exposed too.

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What camera priority mode should I use for HDR photos?

Question

I believe the best way to get HDR shots is by using the Av mode, so the depth of field is consistent across 2-3 images.

Should I be switching to manual mode and changing the shutter speed with a fixed aperture?

Answer

You should use the Aperture priority mode, and keep the aperture the same for all shots, otherwise you could get some odd focus differences between shots. The only downside is if you have to go low on your shutter speed and pick up motion blur.

The easiest thing to do is use the camera settings that do multiple shots (usually -2,0, +2) in rapid succession, in which case you don't need to worry much as the shots go off in seconds.

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Can I use aperture ring of Pentax FA lens in aperture priority mode?

Question

I'm considering getting an FA Limited lens for my Pentax DSLR. The FA series has an aperture ring with an "A" setting for control by camera bodies that support it.

Can I instead use the aperture ring to set the actual aperture value in Av (aperture priority mode), letting the camera pick a shutter speed, or am I limited to the "A" aperture and have to use the thumb dials on the body to control aperture? I don't want to go full-manual mode.

Answer

To use aperture priority on Pentax dSLR with FA lens, you have to leave the aperture ring to "A" and select the aperture on body.

With aperture ring in A mode, the FA lens will behave just like a DA lens. You can use Av mode and set aperture on the body, shutter time will be calculated according to automatically measured exposure.

With aperture ring set on a specific aperture, the body does not know what you have set it to and would not be able to select shutter speed. By default, shutter will not work. You can enable using aperture ring in Custom Settings, but that will just enable using shutter - the lens will be used wide open regardless of the setting on aperture ring.

That's where the "crippled" part of the "crippled KAF2" mount on Pentax dSLR-s shows up - they do not have the mechanical linkage to read aperture settings from an aperture ring.

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What are the benefits of Av vs. Tv vs. Manual exposure modes?

Question

So what's the benefit of using one over the other? The way I understand it, in Av or Tv, you only have to adjust the shutter or aperture, and the rest is done automatically for you...is this correct? Is there some advantage shooting with Av/Tv that I just don't know about?

Answer

First, I don't know, which advantages of Av/Tv you don't know about. :-)

For me, these modes are very useful, when I do not have time for full manual setting and I do not want to use full auto mode.

Sometimes for example I need the camera not to choose shutter speed less than 1/250 (when I use my telephoto zoom) but I am sure, the camera will choose acceptable F-number.

When I have camera on tripod and shoot some static objects, I use aperture priority as the time can be 20 seconds, when necessary.

The priority programs give me relative freedom to set only, what I need without need to care about the other settings. So I can better focus on photo itself - composition etc.

Sometimes I also use full manual mode - when I have enough time and want to fully control the camera.

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Pentax FA lens with aperture priority mode?

Question

I'm considering getting an FA Limited lens for my Pentax DSLR. The FA series has an aperture ring with an "A" setting for control by camera bodies that support it.

Can I instead use the aperture ring to set the actual aperture value in Av (aperture priority mode), letting the camera pick a shutter speed, or am I limited to the "A" aperture and have to use the thumb dials on the body to control aperture? I don't want to go full-manual mode.

Answer

To use aperture priority on Pentax dSLR with FA lens, you have to leave the aperture ring to "A" and select the aperture on body.

With aperture ring in A mode, the FA lens will behave just like a DA lens. You can use Av mode and set aperture on the body, shutter time will be calculated according to automatically measured exposure.

With aperture ring set on a specific aperture, the body does not know what you have set it to and would not be able to select shutter speed. By default, shutter will not work. You can enable using aperture ring in Custom Settings, but that will just enable using shutter - the lens will be used wide open regardless of the setting on aperture ring.

That's where the "crippled" part of the "crippled KAF2" mount on Pentax dSLR-s shows up - they do not have the mechanical linkage to read aperture settings from an aperture ring.

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When should I use which aperture settings?

Question

I just bought a new Canon EOS 60D and working to choose a great lens. I have used DSLR before but never seriously. I have few questions on aperture which might be obvious to many but very helpful to me and possibly to few other who are new. I'll mainly be using aperture priority.

My question is: what should be common value of aperture in following situations? I understand correct value is scene-specific but common values will help.

(Let's assume it's daytime)

1. On streets everyday
2. Indoor.. .Like a living room
3. Park
4. Landscapes
5. In a bar
6. Cityscape

and how will that differ compared to night.

Answer

There is no 'correct' aperture, even for a specific scene. It doesn't just change your exposure, it changes the depth of field of your photograph. Its a creative portion of your composition.

In dimly lit areas like indoors, in a bar, etc - you probably want lower f/stop numbers 1.4-2.8 (bigger apertures) - but only if you want correspondingly shallower depth of field.

Outside in bright light, you may want larger fstop numbers (8+) because you have the light to use it, but only if you want deeper depth of field.

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