De­ploy the full range of com­puter-based blur tools for post-shoot con­trol of depth of field

Digital Photograper - - Techniques -

While many depth-of-field tech­niques can be eas­ily ap­plied in-cam­era, there are oc­ca­sions when al­ter­ations to the range of sharp­ness within an im­age have to be in­tro­duced dur­ing post-pro­duc­tion. There are a sur­pris­ing num­ber of blur­ring tools avail­able in soft­ware pack­ages such as Pho­to­shop, each pro­vid­ing an ef­fect that ap­prox­i­mately sim­u­lates the DOF seen in a dis­crete pho­to­graphic sit­u­a­tion. Cred­i­bly in­tro­duc­ing blur to an im­age can vary from be­ing a rel­a­tively sim­ple task, to be­com­ing a com­plex and time-con­sum­ing en­deav­our. This is the key rea­son for at­tempt­ing to fully con­trol DOF at the mo­ment of ex­po­sure – many of the con­di­tions in which the pro­cesses dis­cussed here may be adopted will be when the pho­tog­ra­pher feels the f-stop-in­duced blur­ring in a shot is in­suf­fi­cient and no re-shoot is pos­si­ble. That be­ing said, in other in­stances post-pro­duc­tion work can pro­duce styles of im­age that can­not be gen­er­ated at the cam­era, such as the pop­u­lar Br­enizer Method de­scribed on these pages. This tech­nique has been em­ployed since the days of film, dur­ing which time some el­e­ment of post-shoot work has al­ways been es­sen­tial for it to work. The rea­son for the fail­ure of sim­u­lated fo­cus ef­fects is the qual­ity of the blend­ing of sharp de­tail with soft, fil­tered ar­eas, es­pe­cially along edges in the scene.

The rea­son for nat­u­ral blur­ring in pho­to­graphs, via aper­ture choice, is the vary­ing dis­tance of ob­jects within the frame from the cam­era po­si­tion. Where false blurs have to be added, care must be taken to cre­ate a re­al­is­tic bound­ary be­tween ad­ja­cent pix­els, where the blur fil­tra­tion ends, to main­tain this il­lu­sion of sep­a­ra­tion. One highly ef­fec­tive so­lu­tion is to ap­ply blur fil­ters on new lay­ers, then make un­feath­ered layer masks to pro­duce sharp, highly de­fined edges to blurred ar­eas. The crit­i­cal el­e­ment is to re­mem­ber that DOF refers to more than just blur­ring it­self. With cam­era-gen­er­ated fo­cus be­ing di­rectly re­lated to dis­tance, ob­ject size in the com­po­si­tion is in­sep­a­ra­bly linked – a fact that must be con­sid­ered when choos­ing to ap­ply a Pho­to­shop fil­ter.

3 LOCK FO­CUS AND EX­PO­SURE As with shoot­ing lin­ear panora­mas, the ex­po­sure can­not change be­tween frames if soft­ware is to be able to merge them later. Take a read­ing and en­ter those set­tings in man­ual mode. Fo­cus may also al­ter, so switch to MF mode once ini­tially fo­cused on the sub­ject.

4 SHOOT, RECOMPOSE, RE­FO­CUS Take your first frame, ro­tate the cam­era from right to left, re­fo­cus man­u­ally if nec­es­sary and shoot a frame ei­ther side of the sub­ject, which should be kept sharp in all seg­ments. Re­peat the process for a row of shots above and be­low this first row.

5 GROUP FILE SE­QUENCE Next open your im­ages in Adobe Bridge or Light­room and cre­ate a Col­lec­tion of your im­age se­quence, or move them to their own folder, for easy re­trieval later. Num­ber your shots by row and seg­ment for ref­er­ence dur­ing the stitch­ing process.

6 STITCH IM­AGES Use man­ual blend­ing meth­ods for bet­ter con­trol. Ex­tend the can­vas of the top-left seg­ment in Pho­to­shop, drag the other im­ages onto the doc­u­ment and ar­range ac­cord­ing to po­si­tion. Use Edit>Auto Align Lay­ers fol­lowed by Edit>Auto Blend Lay­ers set to Panorama, to re­move seams.

7 CROP AND RETOUCH To fine-tune the fi­nal com­po­si­tion, some crop­ping may be nec­es­sary. This will also re­move any rough edges cre­ated by the stitch. While ba­sic pro­cess­ing may have been done on each seg­ment in RAW, fi­nalise the colour of the wider im­age now.

Bot­tomWIDE AND SHAL­LOWthe fi­nal stitched com­pos­ite suc­cess­fully holds at­ten­tion on the sub­ject by min­imis­ing back­ground de­tail, while ef­fec­tively show­ing the in­sect in its en­vi­ron­ment

Be­low STAN­DARD COM­PO­SI­TIONin this shot the pho­tog­ra­pher had to choose be­tween a wide frame and greater back­ground de­tail, or a tighter shot for bet­ter blur­ring

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.