Auto or Manual Focus ?

JohnC6

JohnC6

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I've been taking a look at the issue of photographing steam locos and one suggestion I've seen is to use manual focus on the grounds that the train is generally moving at 60 mpg..that's 88ft/sec. and the auto focus won't be able to cope with that no matter what shutter speed is used. Mine are not generally taken side on but as they approach a bridge or me at trackside. I generally like to be at a minimum 1/640 sec. preferable 1/800 sec. I shoot on Av using A1 Servo. (10fps) and just fire off.I take a few as it approaches and when close keep the shutter button pressed which usually gives me about 8- 10 shots before the loco passes by or under the bridge I'm on.. The suggestion I've seen is to pre-focus on the track at the point you want to get the photo and use one shot and as the loco hits that point take the photo. On the face of it seems logical. However, it doesn't allow for shots to be taken as it approaches and there's the disadvantage that you get just one shot at it but at least it's sharp or should be.. I've done one like this (the second photo) but can't see any difference..I'd rather be in auto.

Is this a valid theory ?

On Auto 44m 1/500 sec
2u43af6.jpg



Manual 84m 1/1000 sec.
11qhct0.jpg
 
I very much doubt that you camera can't handle Servo/Continuous focussing. (I assuming the capability of shooting 10 fps it's a modern beast). Back in the Olden Days such problems were handled by pre-focussing on manual. The more side-on the more acute the problem - I used to lessen this by moving closer to a head-on shot thus mitigating the movement.

A longer shot is going to appear better than a closer or tele shot.

Has your camera got the facility to perform predictive or 3D focussing? I can only speak from a Nikon perspective but that's what I'd use in your situation.
 
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JohnC6 said:
one suggestion I've seen is to use manual focus on the grounds that the train is generally moving at 60 mpg..that's 88ft/sec. and the auto focus won't be able to cope with that no matter what shutter speed is used.
Click to expand...

The AF on a 1D MkIV will easily be able to handle the slow speeds of a lumbering locomotive. My old 50D could happily cope with the dragsters at SantaPod doing a darn sight more than 70 mph.
 
Surely theres enough trains go past in order for you to try both and compare ?...... your answer is whatever worked best :)
 
Always do what best works for you :) As KIPAX says, try both :) I prefer using manual - hones he skills.
 
I've never used manual focus for my railway photography, auto focus has never let me down. Granted, mainline steam runs quicker than on heritage lines but they're limited to 75 (I think) which should be well within the capabilities of a DSLR. Also, given the distance you would be in the photos above, the relative movement of the train across the frame is unlikely to give a DSLR AF any problems.

Suggest you go line side and practice on service trains and see how you get on before trying it on a steam special which you'll only get one shot at (unless you're chasing it!).
 
Many thanks all..I'll stick with auto then.

Barry..As noted by Frank, I have the Canon 1D1V. It certainly should be able to cope. The problem is that these articles aren't dated so it could have been written a few years ago. I started looking because the on some, not all, locos the number on the boiler front wasn't tack sharp. I've googled again and found it. If you go to point (white dot) number 12 you'll see what I read. He's got shots from 1959. I see he's recommending the Canon 100-300. That's going back to 2007…not what you could call 'the olden days' but in terms of advancing technology quite a while.

http://www.wildlife-photos.me.uk/Steam-Railway-Photography(2112071).htm

KIPAX.The two photos above are comparisons but as I mentioned at the top I couldn't see any difference but it does no harm to ask and now I feel happy with auto. Re. trying it out...I'd have to test with diesels because the steam locos can be months apart and when they arrive I don't want to mess up. They move them to Scotland, up north and over to the east coast so I may not get to see them again for 12 months. I'm happy with the answers and will stick with auto.

jpwild..Thanks J. Someone might have had definitive answer..which they have, i.e... auto on a modern camera/lens should easily be able to cope.I'm not that comfortable with manual focus to be honest but if it's a situation that rte quires it then I'll use it.
 
Sure you can get them tack sharp.

Use single spot auto focus and virtually any modern camera can cope.

As has been said practice really does help and steam locos are slow compared to modern day high speed electric and diesel trains.

One thing I would refrain from though is 'machine gunning' your shots. You are much more likely to get failures than putting your effort into one or two really good shots. If you want moving shots, then shoot video.

Modern freight trains will generally run at or slightly faster than steam specials so practice on them.
 
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JohnC6 said:
I've been taking a look at the issue of photographing steam locos and one suggestion I've seen is to use manual focus on the grounds that the train is generally moving
Click to expand...


What you're decribing is "trap" focusing. Focus on a piece of ground and when teh train reaches that point, you shoot.

It's an outdated way of working. It was devised when there was no AF. The problem with that is... you get one shot.

Why anyone would use manual focusing on a moving subject these days is beyond me. Maybe they feel they're being "Proper" photographers if they focus manually or something, but it's just stupid. 60mph is not fast, Most modern AF on continuous servo could keep pace with something way faster than that. Also, remember, while 60mph is not slow, you're a long way away from it in most cases, so the speed the object is travelling across the frame is relatively slow.

Modern DSLRs have crap viewfinders for manual focusing. Proper manual film SLRs have proper ground glass screens, whereas DSLRs have a fresnel screen designed for brightness, but are not very good at allowing you to visually check focus, so you end up using the digital rangefinder indications to confirm focus... which means taking your eye from the subject looking for that little circle to light up to confirm. Pointless. Also, unless you have a full frame camera, your DSLR has a really tiny viewfinder... again, useless for manual focusing.

Stick it on AF continuous servo (or whatever the Canon equivalent is if that's what you're using).

The only time I use manual focusing these days is with static subjects, and even then I use a zoomed in live view to do it, not the viewfinder.

Modern AF is more than a match for such a slow moving subject as a steam train... even if you're right down by the tracks... it will be fine unless you have a completely rubbish camera.

Your included images are way too small for me to check if either of them are sharp. The only way you can do that is to look at the full resolution images from the camera, not a low resolution JPEG on a forum.
 
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The argument in terms of train speed is b*****ks. What matters for focus tracking is not the speed of the object over the ground in miles per hour or feet per second, but speed of movement of the image of the subject in terms of pixels per second.
 
chris malcolm said:
The argument in terms of train speed is b*****ks. What matters for focus tracking is not the speed of the object over the ground in miles per hour or feet per second, but speed of movement of the image of the subject in terms of pixels per second.
Click to expand...


Yes.. relative movement in the frame in other words... as I said. However you're measuring it though.. modern AF can take a lumbering steam train in it's stride.
 
Thanks both.Cleared it for definite. Auto on continuous shooting but I'll do it in two very short bursts as it gets close.

Tomorrow I'm off to Bathampton catch 'Mayflower' and I'll be trackside if I choose location A or just below the train in a field for location B…I haven't been to A before but I'm giving myself enough time to go to B if it isn't a decent spot..or I can't get to it.I use Google Earth and it's sometimes a bit different when you get there..re. trees/bushes. It won't be a full on side-on shot either.

I mentioned above about how articles aren't dated which is annoying...seems that one (the link) above is back a few years.

David…You're right,it wasn't worth posting those two photos. I was looking at the enlarged versions in my Lightroom in the Navigator section in Library that alerted me but strangely on the last photo I took..Clan Line near Twerton, the boiler number was sharper…tack sharp.. at 1:2 which is a larger image than Fill. I'm not sure what size 'Fill' is. Fit is the first enlargement..only slight,not much larger than the thumbnail. Then comes 'Fill' There's 1:1..100% 1:2 which I assume is 50% and 2:1..200%.

I really appreciate all the responses and I'll forget about manual now. I've got good gear and should have had more faith in it. I'll have the Canon 24-105 on a 1D1V.This is my favoured combination unless I'm a little way off up in a field and will use the 70-200 Mk 11 f4. Another excellent lens. So..I'll be posting 'Mayflower,' hopefully, tomorrow evening.
 
Don't get TOO obsessed with sharpness though. Realistically, how big are you ever going top print them? To see the detail you're seeing at 200% in a print you're talking close to A0. You ever going to print that big? Concentrate on taking good photos... no one else will be measuring how sharp they are to such an extent apart from you.
 
Modern cameras can easily cope with fast moving subjects.

I've shot F1 cars at nearly up to 200mph on all my bodies and none struggled, even with teleconverters.
 
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Thanks again,David. At times I drive my wife nuts with my determination (obsession really) to get thing spot on. There's a phrase that just isn't in my vocabulary....It'll do'..Lol. I hear it too often though.

Maybe you could take a look at my photos that I've just posted in 'Transport'. Steam Loco 'Mayflower' and the 4 diesels…coupled. I can't complain about them really. I will get some prints, my wife wants some of my photos around the house so just the size you'd frame and hang. I've said it before about photos on this forum. a very high standard in many cases so there's that for me to think of too and it's good ,otherwise you'd be settling for something, at the very least, less than very good.

Thanks for the contribution,Jim. Appreciated.
 
Took a look, but they're really too low res to establish exactly how sharp they are. They appear sharp at the resolution posted though.
 
As others have said, standard panning technique with servo AF will help you loads. Shooting with shutters speeds that high you ought to be able to keep the backgrounds very sharp too.
 
eejit said:
As others have said, standard panning technique with servo AF will help you loads. Shooting with shutters speeds that high you ought to be able to keep the backgrounds very sharp too.
Click to expand...

Depending on shutter speed though, panning is probably not what's wanted for the type of imagery the OP is producing, which if you look at it, is as much about landscape as it is trains.
 
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