Crop factor seems to come up a lot. Let's start from the beginning.
Crop factor is caused by the fact that the sensor in many cameras is smaller than 35mm film was.
If the sensor is APS-C (NEX-3, NEX-5, Nikon D7000, Canon 5xxD, 7D, x0D, all Pentax dSLRs) then the crop is generally around 1.5x, as the sensor is 2/3 the size of full frame.
With me so far? good.
The issue is that the viewpoint and field of view of the LENS does not change, but because of the smaller sensor size and the therefore restricted view shown to the sensor, it appears as if the lens "got longer". It didn't, it just looks that way. As part of the package, you get effects on depth of field, too (smaller sensor = more of the pic in focus).
Positive: long lenses "get longer". So you'll see a smaller cutout but it will still be detailed. This is good.
Negative: short lenses also get longer. So really wide angle is no longer possible, as you're always working longer than on full frame.
What this is useful for is one thing, and one thing only in my book: comparing what lenses from different systems will do in terms of one another.
Pancake 16mm on APS-C is FF-equivalent of 27mm or so. Pentax' 24mm --> ca. 36mm.
On Micro-4/3 (so a GH-1), it's Pancake 20mm --> 40mm as the sensor is smaller. This is *really* nice to know as otherwise you might be buying what you take as being a "wide" lens and it's really not that wide at all. Back in film days, 28mm was considered "normal" - so that's around an 18mm in crop terms - and anything lower than that was wide. It's not changed that much.
I quite like the Pentax Q way of dealing with this issue, removing the mm numbers from their lenses. I presume the idea is to reduce confusion, but whether it will work or not is another story....
If you want to take, say, car pictures from up close and don't mind distortion, you'll need something shorter than 18mm. 10mm will distort, anything much lower than 14 will visibly distort. If you can live with this, go for it.
If you need examples, go check out pbase and search on the lens. You'll see exactly what it's capable of. I'd strongly recommend this for any prospective purchase.
Another decent article on this (including pics): http://en.wikipedia.org/wiki/Crop_factor
late addition: http://www.kenrockwell.com/tech/crop-factor.htm
The cooler that's in place right now is a passive one, fed by a snail-formed fan which is noisy as hell. So, I removed that and put the 'board in a case... and promptly got a "wii ooo wiii ooo wiii ooo" alarm. Overtemp.
Dumping the fan from a 775 socket factory 'sink sorted that out, but I need a more permanent solution.
So I'm going to get a 92mm fan and wire it in place. I can't be bothered with *another* €50 (there are two machines...) and then no space, so it's going to go like this.
Air sucked in from on top of the CPU, pushed out of the case by the PSU fan. More "warm" air pulled in by a 120mm in front of the old 5.25 optical drive place - which will be converted to 4x3.5" just as soon as I have a decent method to do this, i.e. longer screws or a commercial solution - and pushed out via an exhaust fan at the rear of the case.
I'm dallying at the moment on the idea of an nxzt case, as that would solve the location problems and would probably look good, but I'm also limited to "only" 8 disks there, too. I need to think that one through.
I actually fitted the RAID card last night and right now, the machine spins up with 5 1TB and 1 1.5TB drives in place. The other 1.5 I'm saving for my desk at work (I have 2TB on there at the moment and fully intend to replicate important changes to that disk on a regular basis). I has to have an e-SATA port multiplier, but I don't see that as an issue.
Next question is where all of this is going in the flat. I'm wondering what happens if I move disks around within the zpool... as in they get a new name as they're on a different port. Of course, I could just mark which disk is on which port.
more digging implies something which is actually pretty heavy to deal with. The *minimum* system requirements for FreeNAS8 are now 4GB memory.
What?
When did FreeNAS morph from a system you could run on pretty much any hardware into one which required a serious machine? I know, hardware is supposed to be cheap, but still, this has made me really wonder.
I've downloaded an older version and will try that... and if it doesn't work, I guess I'm going ubuntu and software RAID as this is just silly.
I'm kind of annoyed. Both the P4SCI boards work, and the one I've transplanted into the old midi-tower case I have lying around boots sort-of correctly. Only thing is that it simply won't start FreeNAS.
My previous experience of FreeNAS is only good. It simply ran on old hardware and that was it. Now? I don't know. I've tried pretty much everything I can (HT off, limit MaxVal etc) and it simply won't cleanly boot.
The only question now, then, is what to use instead. It was the ideal solution and I'm incredibly annoyed that it won't work. That the RAID controller doesn't see the disks doesn't really surprise me (I think there's a different issue there, mainly to do with the fact that I'm running a very high power P4 - TDP 87W - off of a minimally-sized PSU, along with 6x1TB drives) but the freenas thing sucks.
I think I'm going to strip to minimum hardware and see if that helps and then call it a night if it doesn't.
As of now, I expect the occasional post in the blog to come from a couple of other contributors, both of whom are part-time photographers. So you might not see just my content here ;)
I'll let them introduce themselves in their own time.
ho hum, the next set of problems is about to arise - there was a joke on a door next to us about breaking stuff, and someone commented on a post-it "HDD factory flooded? Done".
I didn't think too much about it until I saw a post on another forum... and now, I realise, I need to move to get some big disks ASAP or I won't be able to afford them until March. And by then everything will be *full*.
€90 for 1TB and €132 for 2TB is better than some offers I've seen, but still, that's around double the prices last week.
the HTPC now has a graphics card to replace the borrowed PNY one. It's an older Asus one, 8600 chipset - and with S-Video and two DVI-D outputs. Now to find drivers.
Reading over on silentpcreview, the card is four years old and I'm going to have fun making sure it's adequately cooled. The reason for this? The system is supposed to be going into a "radio" from the 50s. Or something like that - it's old, square and wooden. I'm leaving some of the knobs and lights on the front, but the PC is going in the back.
I need to take it apart and find my thermocouple before doing much else, as I need then to create a clear thermal path, probably with some 120mm case fans running slowly to push air out of the back. Luckily, I have a couple of those lying around from other projects.
Pics when I've tidied the garage so I can work in there again.
Now I've bagged another P4SCI, the search is on for a cooler.
Preferably passive, socket 478. I thought I had something useable... yeah, right. I'll put the original back on later after I've polished it some.
The setup is going to be pretty simple: one P4SCi as Firewall, another as server.
Core2Duo as HTPC machine - I'll show the idea for that later - and then the 201 will go into the kitchen with an SB-Live for use as a "radio".
However, both the P4SCis need new PSUs and new heatsinks, as 87W TDP is a hell of a lot and at least one will be banished to a case with lots of disks in it. I might be able to mount it on a wooden wall, but still, it needs a cooler.
If you've got a suggestion (at the moment it's going to be a Zalman 7000), comment!
remember robocopy doesn't like spaces in directory names, so tildes are important (on a Finnish keyboard, bizzarely, it's Alt-gr and umlaut (¨)) - so that means "my music" becomes mymusi~1.
Using /log+: really does speed things up, though it's not too shabby anyway.
So I ended up with
robocopy source dest /w:1 /r:0 /mir /log+:robocopy.log and it got on with it, maxing out USB2 speeds on the external and the same (25MB/s) on the internal.
will just copy everything. Won't disturb modified dates or similar, but will just copy and DELETE AS ON THE SOURCE! So if you're trying to replicate directories across disks (for example because you've got, say 100GB of FLAC files on three external disks) then this is a good way to do it.
Adding a /maxage:30 will also set the maximum age, so if you've got a set of files you've touched recently, that will ignore everything else and only copy the new stuff.
I have no idea if it would be this "easy" with CDs or DVDs, but I'm finding it relatively simple - at least so far - to recover data.
The SCSI disks were a pain. I now have two disks running - one 120GB 2.5 and a very full 60GB 3.5", copying over to a spare disk. I'll have to try and find space to replicate that *tomorrow* as I don't trust the disk that much, but I'm also only copying and not moving.
Still, it's good to see that data is still intact that's 9 years old where nothing special has been done, apart from taking the disk out of the box and putting it - literally - on a shelf to be forgotten about.
I'll try and read one of my old DVD-R disks at some point soon and see how well they work.
All this data recovery will probably lead to an avalanche of new stuff on 23hq, which is where most of my stuff gets kept.
One thing that has struck me is that the DiMAGE 7 I used to use has essentially only had 7-8k clicks. The K10 had 60k in 4 years and the k5 is heading over 12k in 1 year. The '7 was in use for around 4 years, I think. I'll maybe sort some stats out later.
I *will* be troubling GIMP with these, though, as the auto WB feature there is pretty good, even for JPGs. For some bizarre reason I never saved the dimage stuff in RAW (I suspect because it was 5MP and I was using 128MB CF cards at the time) so that's only in JPG. Ah well. I still have it somewhere.
After these, there's a bunch of other stuff to do, but the next thing will be to set up the server and try and get it quiet. That, though, relies on me actually getting a board with twin NICs for use as a firewall. That's proving more difficult than I'd like, though I'm tempted to use the D201GLY2 with PFSense.
I'll explain more about the network setup shortly. I need to go see what my backup restoration is up to.
Edit: oops - I spoke too soon... windows just rebooted.....
There's a listing here - http://www.detailingworld.co.uk/forum/showpost.php?p=3051309&postcount=14 - of some lenses and their usage by a pro 'tog whose work is really rather good. One thing to pay attention to:
"for some distance compression"
Think that through: if you want endless skies and lots of foreground, go as wide as you can. If you want to bring that house a bit closer, use a slightly longer lens. Now, these numbers don't really apply for APS-C cameras (I'll get on to that later), but still, they're a good starting point.
The above stuff should be obvious. It isn't always and walking away or towards something and using a different lens changes the composition in terms of how close things appear to be to one another, all other things remaning equal..
What this means?
On my K5... I might see a scene, with a tree on the left, a car on the right and some beach. If I use a 10mm, I can be standing about a metre behind the car and I'll still get it all in. The sand will appear to go on forever, with a beautiful long stretch of water to the horizon.
Could also be considered boring.
If I go to another extreme and use a 135, then I'd have to walk backwards, but (assuming I have a flat beach behind me) the horizon and sea and sky will not seem so "marlboro country", as the lens compresses. It's different for each lens and some will lend themselves to landscapes more than others, but the concept holds.
Enjoy a lens for the rendering it produces. And if you're not sure what that is, then deliberately go out for an hour or so and take some pics with it. Now go home, take a different lens out of the bag, and take very similar pics with it (won't be the same, but it should be pretty close). Repeat as necessary.
Now go compare the pics. What looks "good"? What doesn't? Did focus always sit correctly? Don't concentrate on the technical correctness of the pic, think about the feel and the attitude it conveys.
Performing sharpness tests with zooms (on a tripod, f-lowest, f8, f10, f14, f-highest) should be on your list of things to do the minute you get a lens. Is the sharpness the same left and right and top and bottom? All the way through the zoom range?
If you've done both of these things - checked capabilties and feel - then you'll have a really good idea of what you can use and which compromises you need to go into before you walk out of the door on the way to your next shoot...you've checked the scientific and soft attributes of your lens, so you can understand which one to use, when.
I own several lenses:
- SMC-DA 18-55 kit. It's not used much.
- Sigma 24-70/2.8 - the 2.8 means it lets lots of light in. Payoff is that it weighs 800g. Front end is also 82mm in diameter.
- Pentax D-FA50mm /2.8 macro - very close focus distances are possible here and that's what I tend to use it for.
- SMC-M 28mm /3.5 - old manual lens I use for video
- SMC-M 135/3.5 - old manual lens I use when I want something small and light and reasonably telephoto. Don't use this much, either.
- Sigma 100-300/4 - most used lens at the moment, but it's a monster, over 8" long and 1.5kg. Needs a monopod and with its hood is a seriously imposing beastie. Does lovely things, though....
Lenses I used to have:
Tamron 10-24 3.5 - 4.5 - wide. Very wide.
Tokina 80-400 f4.5-5.6 - compact tele.
Pentax SMC-M 85/2 - compact portrait lens
Pentax 28-70/4 - very small, very light zoom
What I'd like in addition to these and why:
- 10-17 fisheye. Why? Because you get 180 degrees crushed into one picture. I don't think I'd use it much - I've had a 10-24 before and didn't get on with it. Alternative might be the 16-45/4 as this is convenient - either that or a 17-50/2.8.
- 70-200 / 2.8: sometimes the 100-300 is simply too long.
- 50-135/2.8: indoor, conference / wedding photography: this is *the* lens range for people. Flattering portraits without having to get in their face. And 2.8 means it's easy to isolate away from a background.
Until recently I also had an 85/2 and a 28-70. The 28-70 was replaced by the 24-70 a while back - it's a solid 2.8 all the way through and though it's a *lot* heavier, it's still balanced. The 85 is a true manual lens - like the 135 and 28, you need to set aperture by hand - but I have no problem with that, I just found I was never using the 85. And it's a lovely lens and deserves to be used.
The 85 was bought with portraits in mind, and the 50 does that almost as well. Traditionally, 85 was "the" portrait length, as it's flattering to the face - and f2 is really nice to stop down to f4, get the nose and one eye in focus and stay away from the wrinkles - but on digital, it's a bit 'longer' than that (closer to 120). So 50 is a decent length on crop format and I find mine works great.
The thing about lenses is that they change the way things look depending on both the distance and the focal length of the lens. So a 200 will compress things, a 10 will broaden them. Older lenses tend to be less forgiving here, but that's just something they do.
My personal advice is this: buy a lens - or keep it - because you like what it produces. You like the way it renders colours, skin, textures, shapes, whatever. All lenses have character and it's a good idea to understand what that character is so you can use it when the opportunity presents itself.
The 85 was fantastic for dreamy, floaty portraits. The 50 is great for accurate repro. The 135 gives a lovely seventies, faded colour almost sepia feel; the 24-70 is superb on green but needs to be f14-f16 for best results when further away. The 10 is extreme and sharper at 13 - but it sharpens up beautifully on screen and composition needs to be thought about a *lot* more. The 100-300 simply rocks but is silly-heavy and requires 1/320+.
You can buy and sell pretty much any decent lens for reasonable prices. You'll probably lose twenty, thirty of your favourite currency on the deal - but that's life. You'll be richer in experience as a result.
Don't be afraid of older lenses, too; MF is a skill and it's a difficult one to do well. Practice and you'll understand far more about why certain things work with AF....and if you get to set your aperture yourself, suddenly things get a *lot* more difficult (ha, I have a green button for autometering even with fully manual lenses, because I use a Pentax!) - but again, you learn. No difficulty, no learning....
I got the data back from the original machine. I found the memory.
But *every* other OS crashed.
XP. Win2k wouldn't install. Win7 x64 and x32 (don't touch vista). Clonezilla, SuSE, Ubuntu all gave kernel panics.
I suspect very strongly there's a PnP issue somewhere along the line, but to be honest, I'm not going to worry about it as the data's off the disks now. And onto another, from which I will copy it tonight.
I have lots of posts from a previous blog which went down without warning. So this is a quick test of the text / image combo from there via Google Cache.
this is the kind of thing I like doing. The 100-300 is better than I thought and allows a *lot*, also giving lovely creamy bokeh. Very nice.
Yes, I know it's kind of dirty (hard not to be when you drive as much gravel as me), but the style is what I was looking for - and I'm really glad I hit it.
- lenses: what lens to use for what
- what ISO numbers are for
- why flash is cool
- how to make great landscape photos
- interposing light and shadow and why you should give a toss
- taking great holiday photos
- autumn and why it's the best time of year to be out and about
- DoF and how to use it
- getting whitebalance right every time
- processing RAWs
- Coc, DoF, Hyperfocal distances and applying them
(BTW: those pics from the other morning are at ISO640!)
I basically spent far too much time over the weekend saving data. Old stuff. The machine it was on hasn't been used since 2004 (that's seven and a bit years, count 'em) and yet it booted. I have 640MB of RAM in that and I found it again in a box I wasn't expecting it in - and hey presto, pictures.
So, now "all" I have to do is connect up the other disks - and make sure that the big server actually starts to run and run reliably. There's probably getting on for another terabyte of data scattered across 5-6 disks. Then there's 2 TB on my desktop at work.
The server will get 6TB of disk, which should be enough to be going on with... but not much more than that.
I'll be testing a RAID card in a 478-era P4 with lots of disks attached as JBOD very shortly - as this means I can avoid using the Core2Duo for Server duties and give the RAID card a 512MB cache (found a SO-DIMM, PC133 SDRAM). The Core2Duo box will then play HTPC. If I can find enough RAM.... at least that one's DDR2 and can accept more than 4GB.
Now 'all' I need is a box for firewall; the last one got frazzled by some orange squash.
I realised early this morning that there's something that gets me about answers to many forum questions. Let's not go into the inability of many forum posters to use grammar or sentence structure, that's a rant for another day.
It's about the responder and how they phrase their knowledge. It's apparently quite difficult as an 'expert' to select language which is usable by the person who posed the question. Is elegance or eloquence really that difficult?
Am I being snobbish about this? Maybe arrogant? Probably. I didn't really understand this a couple of years ago, but the relevance of a post defines its usefulness. Seems obvious. Is ignored a lot of the time.
There's a lot of "look how cool I am!" on the boards, all over the 'net; there's the "I registered here to diss x", the "I've been doing this for years" and the tenth thread in a week about the same subject. Sometimes the forum software makes it really hard to find the old threads, but most of the time someone's just not reading. Mp3car is a great example of baptism by fire - if you don't read up on the subject first, you will be flamed. Now is this good? Or is it just a case of "I have such superior knowledge on this topic and feel the need to share it" or "I'm so good it hurts"? I guess what really irritates is the implication "I'm great, I've been doing this since forever" without evidence. There's ample options for providing it, and I think I'm personally looking for proven authenticity, even if it's not really possible in this online day and age. Then there are those who have fantastic skills and ideas - but the sheer volume of ideas prevents them from finishing stuff. Still, it's also obvious they're trying hard to improve and are willing to share their knowledge and experience. I like this very much.
I'm also guilty of showing off - but I'm learning. I suspect part of the reason I try hard not to any more is that this is the way we have to deal with reality at work - if someone doesn't get value directly out of the content, the content is per se wasting their time. That's quite a nice maxim to work to, I think. Minimum fluff, maximum usage.
This is now really strange. I managed to find a 160GB EIDE disk "lying around" - that wasn't NTFS or FAT formatted, and therefore can't contain data. Ooookay... so I try to use it to install XP and then suddenly it throws up a read error on the restart?!
I will give up very shortly on XP, this is its last chance. Someone recommended SuSE, so I think I'll give that a whirl, especially as Ubuntu decided to kernel panic on me.
Hmmm..... ah well, there are worse ways to spend half of Sunday ;-)
is about some very old hardware. very? In computer terms, I guess 10 years is ancient... anyways. It's old. An Adaptec 2940somethingorother (I think it's only a UW, not sure) and the then-massive 36GB disk. With data (pictures) on it, that I want.
I've had to take the machine apart because I'm building a server. And now I'd like to consolidate all the pics onto one machine - there are probably 10 discs around with pics on - and then give it to my wife to say "mark what you want printed, it's all there" - and away we go.
Ha. The 2940 is so old, there's no signed x64 driver for Win7. Oops.
Ubuntu? Kernel Panic.
Then the CD refused to allow itself to be read.
In the mean time, I've changed the CDROM, as I can't get the .ISO I have of XP to work properly. So after burning that ISO onto a CD and wasting several hours waiting for XP to install, I finally have a machine that appears to work. Maybe.
The disks would be "scanned" during the install process - another re-start.
Then the 2940 appeared to cause a hang`- another re-start.
Then Formatting took forever. Then the disc refused to start. Then ... I've been working on this since 5 and I've only just got XP up and running. Meh.
And now I need a mouse on the XP ... but the network wasn't installed. Lovely. Ah well, another installation....
I've been adding recently to another blog - not very much, and only occasionally - but it's now disappeared. There appears to have been a server problem and that particular site ain't gonna come back.
Well, that's not too much of a loss for those guys, but to be honest, I've realised I actually *want* to write some blog stuff.
So. Here we are. I'll probably manage to keep it reasonably on-topic: I work for a tech company, I am involved in the security industry and so have a large quantity of computers at home, some of which I'm fighting with right now. Anything else will probably be shown up as time goes on...
