Completely Dejected (auto focus K5)

How can you use manual focus? Are you using a focusing aid? When I have tried it I can get it pretty close but not close to get an exact focus point at f1.4/f1.8

I don't seem to have an issue with manual focussing - I can usually get it spot-on. If the light is really low I use 'Live view' and magnify the image. If you do this you can get the focus 100% right almost every time and it's definitely more accurate / reliable than AF in low light. If you're taking still life shots or shots of a model who will stay still, there's no reason not to use manual focus. Anyway, most of my lenses are not AF so I don't have a choice with these!

Regards
David

You have a fair point here. In the days of 35mm film SLR's we had massive magnification in our viewfinders and split screens, and focus matte areas. it was pretty easy to manual focus in very dim light. Apart from my Olympus E-1, and a colleagues FF Canon thing, every DSLR I've used is like looking through a distant window, and makes manual focussing much more tricky. You can get a split screen for Pentax, made by Katzeye, which could help for accurate manual focussing

link

yeah I can't get manual focus spot on either. I usually just use a torch to give some light to the scene and sometimes to expose it to - I oft work in very low light and sometimes pitch black - so never without a good cree LED torch

I went shooting with a friend today me armed with a K-7 and him with a Canon 500d, both of us struggled to get AF to work in poor light.
The only difference was when we were forced to pop up the flash, his sends out a strobe like effect with the light from the flash and pretty much nailed the focus every time but I still struggled.

I just did a very quick test between an Olympus E-620 & my Pentax K-5, dim light, a sheet of ukulele chords shot from a 45 angle. I was using a DA 18-55 WR on the K-5, and a 14-42 ED on the Olympus, so both were the supplied kit lenses.

Exposure was f5.6, 1/50sec at ISO 1600 - metered same on both cameras. Auto-focussed using central spot on same line of chords, set frame up identically. Both cameras had no trouble finding the focus.

Getting similar results to OP with the Pentax, every shot front focusses slightly. The Olympus was spot on every shot. I don't have access to any really fast lenses, so the issue is pretty negligible at f5.6. I don't have access tonight to any other DSLR makes, but will try this next week when I'm back at work where we have some Nikon D90's.

I think anyone that is saying they can sharp focus in manual is probably using a larger depth of field and therefore a large margin of error. I cannot see how it is possible to manual focus otherwise.

I'm sorry but this is just plain wrrrrrong ! I bought MF Cosina 55/1.2 and K50/1.2 to use at F1.2 ! Achieving accurate focus is slightly more difficult than at say f2 but with the nice bright viewfinder that a 1.2 or 1.4 gives you, and a custom screen (though one of my K5s has the stock screen and it's still not a problem), finding accurate focus isn't that difficult.

The DoF at f1.2 and say 10' (3m) is roughly 6" (15 cms) if you are steady on your feet and the subject relatively still (e.g standing chatting) then it's not that difficult to attain focus, however by 10m that DoF has risen to a whopping 2 yds (1.83M) !

At f1.4 and using the parameters above then it's nearly 7" (17.5cms) at 3M and 2.7 yds (2.14M) at 10m.

This was shot at 04.00 at a distance of around 18" (45cms) with the only light coming from reflected light from a single lightbulb 5m away. No flash. f1.2, ISO 1,600, 1/6 sec, Hand-held. DoF is 3mm ! Note the Cosina is a little softer than the K50 wide open (funky bokeh though), it looks even sharper before being resized and loaded onto the web, though this one took maybe 6 or 7 efforts before I shot one in focus. I think shooting a lot of hand-held MF macro shots helps to make these shots easier, so what I'm saying is practice makes perfect !

If anyone is finding it difficult to manual focus a lens then first of all make sure the viewfinder dioptre adjustment has been adjusted properly. Point at a blank wall or area of sky, alter dioptre until the lines etched on the focusing screen are sharp. Do not try to focus on something the camera is viewing.

Same here, I can manually focus my A 50/1.2 with a K10D or K20D using the factory fitted screen and I always preferred a matt screen in my Pentax MX.

John

Nonsense. Probably 80% of my lenses are manual focus only and I use them all the time with no problems. The lenses vary from f/1.2 to f/4 maximum aperture. Given the grey days lately they are mostly used at, or close to, wide open. I'll admit to having a better success rate since I fitted a katzeye screen, and to finding focusing much easier with my LX etc., than my K20D. I'm sure those who can afford Zeiss lenses don't complain about manual focus either!

K.

I'm surprised that after all previous discussions about MF nobody seems to understand anything about it

Most modern screens and all Pentax screens are made for slow lenses and regardless of what lens you put on the camera, you only see the equivalent of f/2.4. Only Canon make a screen for use with fast lenses of f/1.2 etc.

Loads of info on the other forum, Ken Rockwell etc. and on this one if you search.
23 pages here for starters link

Womble, if you have no trouble manual focusing then why did you fit a
Katzeye screen?

You said that it isn't possible to manual focus at wide apertures... K was just saying that it is possible, although easier with a split screen.

For me, I find it very hard to MF using the standard focussing screen. I resort to LV or my patented 'somewhere in the middle' technique. (I slowly and smoothly move my focus so I see the object come into focus and then go out of focus... then move the focus back again, and again see the object come into and then go out of focus... on the third pass, using 'muscle memory' I click the shutter somewhere between the two points!)

It sometimes works!

That doesn't prevent you from using them:

[IMG]http://i884.photobucket.com/albums/ac49/johnwhit24/Lens%20Tests/Yankee_Candle.jpg[/IMG]

K20D + A 50mm f/1.2

I used one of these in the MX for years:

[IMG]http://i884.photobucket.com/albums/ac49/johnwhit24/Lens%20Tests/circle.gif[/IMG]

SE screen

John