Go Back   Steve's Digicams Forums > Digicam Help > Newbie Help

Reply
 
Thread Tools Search this Thread
Old Aug 28, 2004, 5:54 AM   #1
Junior Member
 
Join Date: Aug 2004
Posts: 6
Default

It seems that Steve highly recomends af-assist lamps,but many camera companys are still not using them. For example,the new Fuji. I am interested in a 3.2mp or a 4mp (and if the price was right,maybe a 5mp) but I don't have alot of choses out there. SO,do I really need one? I thinkI need one?But I'm not sure.

As a newbie,I guess I understand how they would improve your pics when you have a definite suject but. I was wondering how the lamp affects landscape photos?


daddymo3 is offline   Reply With Quote
Sponsored Links
Old Aug 28, 2004, 9:03 AM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

daddymo3 wrote:
Quote:
It seems that Steve highly recomends af-assist lamps,but many camera companys are still not using them. For example,the new Fuji. I am interested in a 3.2mp or a 4mp (and if the price was right,maybe a 5mp) but I don't have alot of choses out there. SO,do I really need one? I thinkI need one?But I'm not sure.

As a newbie,I guess I understand how they would improve your pics when you have a definite suject but. I was wondering how the lamp affects landscape photos?
Autofocus Assist Lamps would have no impact on a distant subject. They have a very limited range. They help the camera to "see" the contrast in your subject in dim light. The working range of most of these lamps in compact models is from around 6-10 feet (although asome are good for alittlemore range).

Although, I agree that these can be helpful indoors in low light, I personally don't like them. Theysometimes ruin facial expressions in your subject when they see the light. I feel the same way about red eye reduction flash modes. When the subject sees the preflash that these modes use, they tend to change expressions, look away, etc. So, they can ruin candid shots.

You'll need to decide how important autofocus accuracy is indoors, as an Autofocus Assist Lamp can definitely help in this area with many models. Steve usuallly discusses Low Light Autofocus Ability in each camera's review conclusion section. There is a big difference in low light focus ability between models (regardless of whether or not they have an AF assist lamp)
JimC is offline   Reply With Quote
Old Aug 28, 2004, 9:41 AM   #3
Senior Member
 
Mikefellh's Avatar
 
Join Date: May 2004
Location: Toronto, ON, Canada
Posts: 1,707
Default

Here's how autofocusing works on most digital cameras (in a simple explanation), so you can see the reason why an AF-Assist lamp would be necessary:

http://www.howstuffworks.com/autofocus3.htm

From that page you can see that the camera needs a certain amount of light to see the difference between light and dark areas of the photo. Many cameras also have manual focusing which can be used negating the need for the AF-Assist lamp.
Mikefellh is offline   Reply With Quote
Old Aug 28, 2004, 1:56 PM   #4
Senior Member
 
Chako's Avatar
 
Join Date: Jun 2004
Posts: 301
Default

I am with JimC with that. I find them to be a love/hate feature.

When I bought my spanking new Pentax SF10 in 88, it was fun to see the faces of people when the camera could focus in total darkness. I used to bring them into the darkroom and show them this neat feature.


Then I bought a dedicated flash witha IR focus aid..only stronger then the one on the built in flash. I wasn't so pleased when a few weeks later, I was assigned to take photos of a school play for the yearbook. To my dismay, the more powerful focus aid would illuminated the dark play admirably. It caused half the audience to look around wondering where the special effects came from. Worse yet, the audience could not see the intense red beam, but the actors could...and I remember one student forgetting his lines after being blinded by the focus aid on the flash unit. No way to turn off the feature either.

They are only good for short distances. They are not good if you like to do people photography, or wildlife. They are good if your planing on taking shots using your AF sensor in really dark situations. Not so good for landscapes though.

Chako is offline   Reply With Quote
Old Sep 2, 2004, 3:20 PM   #5
Senior Member
 
Join Date: May 2003
Posts: 180
Default

I fully respect JimC's views but as a family point and shoot guy myselfa good AF Assist is a requirement for any camera of mine.

Having been used to the excellent AF lamp on my old Sony P52 I was very dissapointed when I had canon A75 on trial a few months ago. These are known for a poor AF assist and the focus errors produced with family gatherings indoors at night were difficult to accept...you needed to use manual focus a great deal for decent results.

When I finally upgraded it happened to be to another Sony camera, again with a very effective AF lamp and I'm pleased I did.

When on our family summer holiday recently we were in loads of dimly lit museums and activities where it was great to get some really effective point and shoot results of the kids. Some were in completely dark rooms and it is brilliant to fire off a quick shot and have it look like daytime in perfect focus.

Jim comments the AF assist range may be poor. Well not with Sony, their lamp seems to be effective well beyond flash range (I would guess 15ft+) which is all you want. No point in the AF lamp getting focus on something that will not be lit surely??

You might say "well what about nighshots of landscape"......fair enough but you will be on a tripod and fiddling with exposure times etc so setting the focus manually in that situation is no big deal.

I've posted elsewhere that I'm getting great results from a small Vivitar slave flash with my Sony P12. Add that to the reliable AF lamp and you have the tools for some surprising results in the complete dark. Took some of the kids watching a presentation in a very small museum theatre. It was too dark to see where they were sitting excatly but I roughly aimed with the camera in one hand and the slave in the other held out sideways to the extent of my arms length.

With the camera button part pressed for a split second the red AF lamp showed me excatly where to point the camera, the slave took all the harsh shadows out of the image and punched lightinto the corners of the room.

Mind you when I buy the second slave flashI'll run out of arms!

David




Cybershot455 is offline   Reply With Quote
Old Sep 2, 2004, 8:21 PM   #6
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Cybershot455 wrote:
Quote:
Jim comments the AF assist range may be poor. Well not with Sony, their lamp seems to be effective well beyond flash range (I would guess 15ft+) which is all you want.
The Sony's AF Assist Lamps do work well (which is why I said "the working range of most..."). The compact Sony models havea bright focus assist lamp (definitely different than some of the other models, like the Canon you mentioned). The Sony AF assist is so bright that the first time I took a photo of my wife with a Sony DSC-P10 last year, she asked in an obviously annoyed tone "can't you turn that light off"? Of course, I obliged (at least you can disable it). :-)

Yes, they help Autofocus Accuracy. Are they good for all conditions? You'll need to decide. Personally, I don't like them (IMO, they tend to spoil facial expressions and keep you from getting candid shots). However, I can understand why some users do prefer them, since they improve autofocus accuracy and reliability indoors.
JimC is offline   Reply With Quote
Old Sep 3, 2004, 3:27 AM   #7
Senior Member
 
Join Date: May 2003
Posts: 180
Default

Jim,

There is perhaps a wider issue involved here than the views of the tiny percentage ofcamera userswho post to these forums (that include me!).

When Steve reviews cameras without AF Assist lamps, or ones that are useless, I think he is right to grumble.

You see these cameras we are talking about are firmly aimed at the point and shoot user. Your camera is such a model, as is mine.

We (you and I)are both experienced photographers and look at things way beyond the target buyer for these models. This is not the norm.

At a recent family gathering, which was pretty typical of an average set of digicam users, there were ten cameras. All were digital and of the verycompact type, just one was a bit different in having a slightly larger body with a 6x zoom.

One of the other users was an ex-SLR man but he never used anything other than auto-everything with his digicam. I was the only person who was considering the "photography" aspect, all the otherninewere "point and shooting".

So nine out of the ten would not have had a clue how to set a manual focus distance, and no wish to do so. As far as they would be concerned their cameras either "worked properly" indoors or were useless if they didn't.

Until some radical way to focus in the dark is adopted then a good AF Assist is probably the only answer for the masses who are buying these compacts, they just want to turn on and push the button!

That is why I look at something like the Fuji E500 4MP with frustration. A well specified £200 point and shoot that can't focus indoors at night!

I accept it is a completely different matter for the digital SLR and pro users who are looking for a far more advanced shooting result.

David
Cybershot455 is offline   Reply With Quote
Old Sep 3, 2004, 3:54 AM   #8
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Some models without an Autofocus Assist lamp work well indoors, and some models with Autofocus Assist lamps don't (some are so weak that they tend to focus just as well without them at most subject distances as they do with them).

IMO you need to judge each model individually. That's why I suggested this in my original post:

"You'll need to decide how important autofocus accuracy is indoors, as an Autofocus Assist Lamp can definitely help in this area with many models. Steve usuallly discusses Low Light Autofocus Ability in each camera's review conclusion section. There is a big difference in low light focus ability between models (regardless of whether or not they have an AF assist lamp)"

Does it hurt to have an AF Assist Lamp? Nope -- not if you have a way to disable it for users like me that don't like them. Ideally, all consumer models would have a decent IR Assist Lamp (with good range) that you can disable if desired,combined with external passive sensors (these systems are being seen on more cameras now), and very good algorithms for contrast detection (and let's includeusable manual focus, too).

But, cameras'Focus Systemsaren't always ideal (even those with AF Assist). So, I'd recommend judging each camera's low light focus ability on a case by case basis.
JimC is offline   Reply With Quote
Old Sep 3, 2004, 10:03 AM   #9
NHL
Senior Member
 
NHL's Avatar
 
Join Date: Jun 2002
Location: 39.18776, -77.311353333333
Posts: 11,547
Default

There's a reason as to why manufacturers don't enable the IR beam on their digital cameras: Most digicam use their internal CCD to do the AF focusing. The problem is theses same CCD have an IR filter (to reduce another source of noise) in front of them making them blind to the same IR signal that help the camera focuses in the 1st place.

Did anyone notice the external flashes on Canon/Minolta/Nikon and others all have IR beam when mounted on their film or dSLR cameras, but are disabled on all their digicam? (G5/G6, A1/A2, CP5700/8700 etc...) or uses an AF illuminator beam in the visible spectrum of their CCD's instead -> If it's visible to the CCD everyone will see it as well! :evil:

Hint: If anyone want to shoot Infrared pictures, pick a camera that uses IR beam for their AF! :idea:
NHL is offline   Reply With Quote
Old Sep 3, 2004, 5:04 PM   #10
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

That's what I get for responding to posts at 3:54AM (I couldn't sleep last night).

You're right. Iwas participating in a thread discussing the same thing recently (why not use IR Assist lamps onDigicams). The hot mirror filters over the CCD's in newer prevent it -- as you pointed out.

I still have aCoolpix 950 that is IR sensitive(but it didn't have an AF Assist lamp either).

I can still remember buying hot mirror filters for an older model Epson digicam to try and reduce purple fringing (of course, it didn't help anything).That IR caused purple fringingwas only the popular theory at the time).

I'm not sure that hardly any digicam models ever hadtrue IR Autofocus Assist Lamps anyway (unless you know of any). Mostwere just "near IR", and still visible.

I can remember the AF beam from an Olympus C-2500L I owned quite a while back. Itwasn't IR, either -- otherwise, it would not have been visible(I suspect it just used a colored lens over the lamp). The same probably applies to any other "visible" AF Lamp (not really IR).

So, I vote we use sonar next (at a frequency notaudible to humans of course, with the ability to disable it around your pets). :-)


JimC is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 2:47 PM.