Lens calibration (1 Viewer)

Have been looking around the internet for various ways to calibrate lens/camera combos.

Adobe do a free lens profiler tool that is compatable with Photoshop CS5 (unfortunately this no bucks tool needs big bucks software), seems a perfect way to iron out anomalies of each lens - TC combo with some pre programmed pre sets (other lens presets are free downloads from users or by Adobe themselves, Camera RAW 6.2 has my Sigma 150-500mm APO).

But I was interested in Datacolor's new 'SpyderLensCal' tool, about £50 in the uk. This tool allows you to fine tune focus with various lenses that you use. You simply set the target up, focus on the target spot and take a picture, review it to find where the lens true focus point is and adjust accordingly (if your camera has focus fine tune, my D7000 does). But then looking at it again, I am sure I could make one (just rip the design). If you had a good high resolution printer, just print some targets and stick on some sturdy backing, it looks like the 'rule' is at a 45 deg angle.

I dare bet Paul would have made by tommorow

All you need is this chart. You can see the full one further down the page, and can you download and print.

I've had this chart for about 3 years now. It works fine, just remember it needs to be very flat, so printing on thin paper is not such a good idea, as thin paper never seems to lay flat enough. You could, as you say, print on paper and then stick on card, but white card would save you the bother, bearing in mind your printer can only print upto a certain thickness

http://focustestchart.com/chart.html

Any kind of grid, even a bar code on a box will tell you if your lens has a front- or backfocus issue, and allow to control the success of your tuning attempts.
This is another version of test chart, similar to the one mentioned above ....
http://www.loncarek.de/pages/Articles/FocusTarget

I wouldn't spend money, for sure not $50, on a device like the spider thingy ........

Ulli

thornlv said:

I dare bet Paul would have made by tommorow

Click to expand...

I don't use any form of focus confirm, so no I wont. 8-P

Paul.

I had seen the chart that musoman pointed out, looks quite interesting. Seaspirit's recomendaation looks even better as its practically just like the Spyder one.

Paul doesnt need it as he has bionic eyes.

Bionic eyes has nothing to do with whether a lens is back or front focusing.

A lens can still do this with manual focusing, so if you feel like checking out your lenses, the chart will help, especially if your camera has the ability to adjust for this.

Can you camara store parameters for each lens?

Front or back focusing problems when manually focusing and without focus confirm could be down to a number of reasons. Things like the diopter setting, the focusing screen could be out of alignment or need shimming, the users eyesight and their ability to manually focus accurately. I'd imagine it's a totally different set of issues than when allowing the camera to automatically focus.

Paul.

Spot on sir.
My biggest focus problem is me.

On side note, though i have the chart, i could only ever check my lenses, and thats it. I have no ability to store any corrective info like Thorn, but my lenses seemed ok really.

Same here, the 450D has no way to store lens data.

Paul.

I can store fine focus settings for any lens, as long as it transmits lens info. The bayonet rings of my SWED80 setup all have AF chips on, with corresponding lens info programmed so I could in theory store those as well.

I see what Paul is saying about manual focusing, I too feel it is important to get the viewfinder diopter right. I do this every shoot with a 50mm fast lens, autofocus on a target (usually a book) then set diopter to that (till its the sharpest with my eyes.

Since getting my D7000 I have read many forum postings of people complaining about soft focus, although I dont think I have a problem with mine I would still like to check the accuracy and DOF. So I feel these focus targets will help me check that, correct any and just basically learn about DOF etc etc.