DoF Preview Button - Junk?

[SYS]

The other day when I was playing around with the hyperfocal distancing for DoF with my 20D, I thought I'll give this button a try. My initial reaction to this feature is, "huh? Is this a junk or what?"

Is my initial reaction really grounded in my ignorance or do others also find this feature useless?

[Mark_Cohran]

It's not junk. It can be useful in certain situations (macro, studio, some nature photography), but I don't use it that much. Maybe others use it more. I'm curious, though, why did you get the impression that it was "junk?"

Mark

[Jon]

It can be useful when you come to grips with it fully; it'll be easier to work with at mid apertures than at the extremes, but in addition to seeing DoF, it'll also let you pre-judge the extremes of highlight and shadow areas.

[SYS]

I'm curious, though, why did you get the impression that it was "junk?"

Mark

Of course the part of the reason for my reaction is that it's pretty useless for any apertures towards smaller openings (11, 16, 22), but even with the wider openings, my eyes can hardly discern what it's theoretically doing, i.e., focus vs. out of focus areas. I frankly don't know how you guys can discern the difference unless you have super sharp, perfect eyesights... which I don't...

[tiha]

DOF button has always worked that way - darkening the viewfinder image. You're lucky that you didn't use some camera that did metering while lens was stopped down (eg. Pentax SP1000)! Well, that was awful! ;)

[ron chappel]

You're not far wrong SYS,i too despise trying to use it for judging DOF.

Now that we have digital cameras we don't have to stuff around with such silliness-just take a pic and look at the screen.
Sure the screen is really big enough for (acurately) judging DOF but it's a whole lot better than looking into a super dim viewfinder.
Interestingly i find i can use the screen on my 300D to see if i got DOF right but often fail to spot wether pictures are sharp or not.

[neil_r]

No and Yes in that order ;)

It can be really useful when determining DOF as you get more familiar with the camera and lens combination and start to "just know" what the DOF will be then perhaps less useful. But for those critical shots, it is very useful indeed.

N

[SYS]

DOF button has always worked that way - darkening the viewfinder image. You're lucky that you didn't use some camera that did metering while lens was stopped down (eg. Pentax SP1000)! Well, that was awful! ;)

I've noticed that the viewfinder does get lighter with the wider opening, so my guess is that it may be more useful for least DoF shots.

[neil_r]

I've noticed that the viewfinder does get lighter with the wider opening, so my guess is that it may be more useful for least DoF shots.

The oposite is in fact true. When you have the lens wide open the DOF button has no affect at all.

N

[jfrancho]

It works fine on my camera, though can be difficult, or of little help in lowlight situations, but you'd be running wide open in those situations without a flash, anyway. You need to really look at a specific area to see the difference - it has the same effect as squinting your eyes.

[Anders Östberg]

In practice, especially with the dimmer dSLR viewfinders, I think it's junk.
I wish it would toggle mirror lockup on and off instead. :)

[mbze430]

Wow, I can't believe I am reading this one.....

This is infact the most useful tool on the Canon camera, because in the old days, stop down metering was the way you can only tell 1) your WYSIWYG DoF, and 2) metering while the lens is stop down.

You guys should consider yourself lucky that you can meter any apeture without actually stopping down.

The DoF button is there because without it, you be missing one of the thing from the old days. It is EXTREMELY useful during close up and macro photography.

Matter afact I just taugh one of my friend how to look through the Viewfinder with the DoF to evaluate. And He has taken Photography class, which apparently they don't teach you that....

[DocFrankenstein]

It's not junk if you have a full frame sensor with bright viewfinder.

In consumer cams it's close to useless.

[Anders Östberg]

I think it's unfortunately especially useless for macro work as the dim viewfinder turns more or less black at such small apertures.

[dcbeattie]

Read this.....
http://www.photofocus.com/showarchive.php?aid=161&cid=4

[Streetshooter]

I use it alot cause I work with hyperfocal distance all te time. It worked fine on my 20D and works fine on my 5D.....what did you expect it to do? it shows the near and far distance focus points flawlessly.......if your not sure of the effect...then shoot a frame and use the led for reference......it is one feature on these cameras that I can not do without...don

[SYS]

Read this.....
http://www.photofocus.com/showarchive.php?aid=161&cid=4

Thanks for the link!!

[SYS]

I use it alot cause I work with hyperfocal distance all te time. It worked fine on my 20D and works fine on my 5D.....what did you expect it to do? it shows the near and far distance focus points flawlessly.......if your not sure of the effect...then shoot a frame and use the led for reference......it is one feature on these cameras that I can not do without...don

Well, sounds like I need to spend more time experimenting with the button...

[jfrancho]

I think it's unfortunately especially useless for macro work Actually, I think this where this feature becomes quite useful.

[RichardtheSane]

Slap a speedlight on top of your camera...
Then when you press the button you get a very handy strobe for a second which is mighty useful in 'brightening' the frame on the smaller viewfinders.

[Anders Östberg]

Actually, I think this where this feature becomes quite useful.

If you quote me then please include the whole message so as not to change the meaning of what I wrote...

[MiG82]

In consumer cams it's close to useless.

WARNING! SNOB ALERT!
(I presume that you mean the 20D is a consumer cam. If so, the 1D is just consumer cam for more wealthy consumers.)

[SWPhotoImaging]

In the olden days . . . .

When I shot film using 35mm SLR's, the DOF preview was pretty helpful on occasion (bright, full-size 35mm viewfinder). When I started using a 10D, the small dark viewfinder rendered DOF preview pretty much useless, at least for my eyes.
When I recently acquired a 5D, I started playing with DOF preview in certain situations again. Although the focus screen isn't as good as the old 35mm SLR's (no split prism), it is usable, and a huge improvement from my 10D.

[jfrancho]

I think there are two issues here. On one side, people experienced with film slr cameras are used to a much larger, brighter viewfinder. The viewfinders in 1.6 crop dslr is not nearly as large, and I don't feel that the viewfinder has the best technology applied. On the other side, some may not be fully understanding what to look for when using the dof preview, and may have expectations that are too high. It isn't obvious, if you can't get past the darkview. When I set my zoom lens to f/22 and look at a scene that has a a lot of depth, I focus on something close, the background is fuzzy. With the dof preview pressed, it is much darker, but I can see that much of what is behind what I focussed on is clear and sharp - and this is at night lit with just 3 - 40w inc. bulbs in a ceiling fan. That is a dramatic example that I urge the naysayers to try out. Now start trying it out using a more reasonable deep dof setting of f/8 - f/11. I don't think that the tool is something that everyone should use, but just calling it junk because it is a subtle tool, isn't really correct either. I don't have the greatest eyes either, slightly nearsighted, but I would be disappointed to see this feature disappear on new models. It's more useful to me than Av/Tv/Program mode and maybe even auto focus. Well, OK, I was exagerating on the last one.

[ijohnson]

Put a wireless ST-E2 transmitter on your camera and a couple flashes around the subject, then push the button. It is VERY useful in that case.

Otherwise, play with it more. It is a bit confusing and only useful sometimes.

[bolantej]

I forgot mine had one.

[SYS]

You know why I'm now completely addicted to this forum, such that I cannot stay away from it even for a few hours?

It's because of you guys and your ever helpful and insightful responses, regardless of whether it's for or against a particular issue or question. Just wonderful forum this is.... (Okay, I HAD to get that off my chest...):D :D :D :D :D :D :D :D

[mbze430]

In the olden days . . . .

When I shot film using 35mm SLR's, the DOF preview was pretty helpful on occasion (bright, full-size 35mm viewfinder).......

Hahah :D Guess you weren't that olden.

[ron chappel]

Read this.....
http://www.photofocus.com/showarchive.php?aid=161&cid=4

Ahh,i've been looking for that article for a year or two! Thanks!!!

I'm pretty sure it won't have much effect on how i use the DOF button (or not as is the case) but a very interesting article just the same

[Lester Wareham]

I would not pay for a camera that did not have stop down pre-view, no sir!

[MagentaJoe]

I would not pay for a camera that did not have stop down pre-view, no sir!

I'm with Lester on this one. When shooting manual I need it. I've become so acustomed to it. I started my SLR learning on a Nikon FM 20 years ago and found it to be invaluable. I just continued onward through different cameras and never really thought about it until I stumbled across this thread.

Learn to use it in the right situations and you will wonder how you ever lived without it.

[CyberDyneSystems]

mbze has it.. your looking at it backwards.

You get to allways use your camera's af and compose etc.. with all the light your lens can gather.. This is the feature..

The DOF preview button is simply there to give you back the functionality that you would have with a manual aperture ring. However the gains of the auto aperture far outweigh the loss in 95% of shooting, and what you would lose you don't because of that simple little "junk" DOF button.

[Cadwell]

Actually the DoF preview button is incredibly useful. Consider the scenario: you're doing a shoot in a dark hall, using flash. Suddenly you drop a CF card on the floor and it bounces out of sight. Now, instead of scrabbling round on the floor in the dark trying to find the card by feel, just hit the DoF preview button. Your flash gun strobes at high speed giving you a handy light source with which to retrieve your missing card!

So helpful of the Canon engineers to design this great feature in. They really do think of everything!

[MagentaJoe]

Your flash gun strobes at high speed giving you a handy light source with which to retrieve your missing card!

Very funny because it's true. I've done this very thing. :D

[ConradB]

Maybe its just me but I use it nearly all the time for everything except landscape photography...

[DrPablo]

Here's an alternative use of the DoF preview button. My otherwise magnificent Tokina 12-24 has developed a problem with its aperture leaves. Often when I stop down beyond f/6 or so they get stuck closed, the viewfinder dims, and I get an error 99 message. I just turn the camera off and on, then hit the DoF preview button about 10 times, and it actually jiggles open the aperture leaves. Cool, huh?

Yes, I'll send it in for servicing, but I'm about to take a trip to Hawaii in a few weeks, and I need my superwide for pics of Waimea Canyon, so I'll deal with its problems after I get back.

[SYS]

Here's an alternative use of the DoF preview button. My otherwise magnificent Tokina 12-24 has developed a problem with its aperture leaves. Often when I stop down beyond f/6 or so they get stuck closed, the viewfinder dims, and I get an error 99 message. I just turn the camera off and on, then hit the DoF preview button about 10 times, and it actually jiggles open the aperture leaves. Cool, huh?

Yes, I'll send it in for servicing, but I'm about to take a trip to Hawaii in a few weeks, and I need my superwide for pics of Waimea Canyon, so I'll deal with its problems after I get back.

Well, I always knew that I could count on this forum to learn all sorts of new things.... :lol: